Army

This page deals with the recruitment and maintenance of armies. For specific combat mechanics see land warfare. For different individual unit types see land units. For Mercenaries and special units see Special land units

An army refers to a country's land forces.

The basic unit of land forces is the regiment, each consisting of 1000 soldiers at full strength. Each regiment is classed as Infantry, Cavalry or Artillery. Regiments are grouped into armies. Each army can be led by a general or conquistador.

Recruiting an army

Recruiting regular forces requires an owned, cored, unoccupied province to recruit in, and three resources: manpower, ducats, and time. Each province can recruit one regiment at a time, though multiple regiments can be queued up in a single province. Regiments can be recruited in several ways:

• the Recruit Regiments button in the province window
• selecting the unit type in the land units tab of the macrobuilder and clicking on a province to recruit them(shift-click recruits 5 regiments and ctrl-click recruits 10)
• selecting an army template in the land units tab of the macrobuilder and clicking on a province starts recruiting an army of a specific composition
• Conform to Template button in the army window (needs Cradle of Civilization) to start the recruitment of missing regiments
• the + buttons in the army window starts recruiting regiments into the army(needs The Cossacks)

When multiple regiments are recruited at once, the construction will usually be spread over multiple provinces and the regiments will automatically move to the province where the construction was started and join together into one army(either the army into which they were recruited, if that army is still in the province, or into a new army).

The base cost and time of a regiment depends on its type; this is then adjusted by any modifiers, in particular any buildings the province might have. Regiments start with 50% of maximum morale.

Manpower

Main article: Manpower

It takes 1000 manpower to recruit a regiment. Manpower is also used for reinforcing depleted regiments.

Regiment cost

Regiment cost is computed as follows:

${\text{regiment cost}}={\text{base cost}}\cdot {\text{max}}\left(100\%+\sum {\text{regiment cost modifiers}},20\%\right)$

Base cost

The base costs for recruiting a regiment are:

• 10 for infantry
• 25 for cavalry
• 30 for artillery

Regiment cost modifiers

Regiment cost may be affected by general and type-specific modifiers which are summed.

General modifiers

General modifiers reduce the cost of all types of land units.

	Conditions
−20%	as Tengri country
−5%	for trading in iron
−10%	with parliament and “Expand the Army” as active issue
−10%	owning Moscow Kremlin at Magnificent tier while its province's culture is accepted and is in the East Slavic group, Slavic group, or is Roman
−33%	as optional difficulty bonus (for the player (very easy) or the AI (very hard))
+1%	for each percentage point of inflation

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−10%	Chernihiv traditions Karelian traditions Kikuchi traditions	Quantity idea 3: Enforced Service Armenian idea 5: Sygnakhs Colonial idea 5: Colonial Militia Great Armenian idea 5: Sygnakhs Polish idea 5: Wojsko Komputowe	Lur ambition Toki ambition	Expansion-Defensive: Local Army Organization Plutocratic-Trade: Trade Kontor Network
−5%	—	Plutocratic idea 1: Tradition of Payment	—	—

There are also many modifiers from decisions, events and missions that affect regiment cost.

Type-specific modifiers

Some specific modifiers reduce only the cost of one unit type.

Infantry

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−20%	Berg traditions Mewari traditions	Burmese idea 7: Bayingyi Imerina idea 7: Foloalindahy Maratha idea 3: Peasant Soldiers	Georgian ambition	—
−15%	Ava traditions	—	—	Indigenous-Economic: The Three Sisters
−10%	Butua traditions Guarani traditions Jaunpuri traditions Lorraine traditions Malvi traditions Maravi traditions Nivernais traditions Polotskian traditions Sistani traditions Somali traditions	Arawak idea 1: Warrior Culture Bulgarian idea 4: Reform The Army Interlacustrine idea 5: Emitwe Kongolese idea 4: Initiation Rites Montenegrin idea 3: Clan Society Odoyev idea 5: Cities of the Upper Oka Valley Piratical idea 3: Buccaneers Romanian idea 5: Peasant Soldiers Slovak idea 5: Town Air Liberates Teutonic idea 1: Reform the Army Yaroslavlyian idea 3: Reform Boyars Zaporozhian idea 7: Army First	Baden ambition Plains Native ambition Tupi ambition	Court-Quantity: Plentiful Materials Act

There are also many modifiers from decisions, events and missions that affect infantry cost.

Cavalry

	Conditions
+20% / −20%	from cossacks estates (scales with loyalty and influence) (only with )
−20%	from tribes estates at high loyalty (scales with influence) (only with )
−10%	from trading in livestock

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−33%	—	Horde government idea 1: Horse-lords of the Steppes	—	—
−20%	—	Aristocratic idea 3: Noble Connections Aq Qoyunlu idea 2: Unite the Clans	—	—
−15%	Ilkhanid traditions	Scandinavian idea 5: Finnish Hakkapeliitta	—	—
−10%	French Ducal traditions Fulani traditions Hejazi traditions Indian Sultanate traditions Khivan traditions Polish traditions Takeda traditions Transoxianian traditions	Adalite idea 4: Mujahidun Cavalry Al-Haasa idea 1: Desert Warfare Arabian idea 2: Arabian Horses Beloozero idea 1: Martial Heritage Charruan idea 4: Horse Adoption Circassian idea 1: Horsemen of the Steppe Couronian idea 7: Promote the Curonian Kings Croatian idea 1: Hrvatski Ban Mazovian idea 4: Szlachta Zasciankowa Nanbu idea 2: Owner of the 'Nine Gates' Odoyev idea 3: Commit to Tatar Ties Oirat idea 1: Fearsome Warriors of Tumu Permian idea 2: Turkic Mercenaries Punjabi idea 6: Strength of the Misls Ryazan idea 2: Tatar Mercenaries Samtskhe idea 6: Frontier Warriors Serbian idea 3: Home of the Hussars Shiba idea 5: Oshu Ties Swedish idea 3: The 'Hakkapeliitta' Teutonic idea 1: Reform the Army West African idea 5: Royal Stables Yaroslavlyian idea 3: Reform Boyars Zaporozhian idea 7: Army First	—	Aristocratic-Economic: The Court of Wards and Liveries
−5%	—	Mahri idea 5: Mahra Camels	—	—

There are also many modifiers from decisions, events and missions that affect cavalry cost.

Artillery

	Conditions
−10%/−20%	Holding Falun Copper Mine at ''Significant'' and ''Magnificant'' level

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−20%	—	Smolenskian idea 4: The Great Foundry	—	—
−15%	—	Rajputana idea 6: Expanded Artillery Arm Transoxianian idea 4: Turkoman Cannoneers	—	Court-Quantity: Plentiful Materials Act
−10%	—	Austro-Hungarian idea 7: The Future of Warfare Russian idea 3: Russian Artillery Yard	—	—

There are also many modifiers from decisions, events and missions that affect artillery cost.

Recruitment time

The recruitment time of a regiment is computed as follows:

${\text{recruitment time}}={\text{base time}}\cdot \left(100\%+\sum {\text{recruitment time modifiers}}\right)$

Base time

The base time for recruiting a regiment is:

• 60 days for infantry
• 90 days for cavalry
• 120 days for artillery

Recruitment time modifiers

Recruitment time can be affected by countrywide and provincial modifiers which are added.

Countrywide modifiers

	Conditions
−20%	for trading in copper
−10%	with parliament and “Expand the Army” as active issue
+2%	for each point of war exhaustion

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−10%	Cornish traditions Iwi traditions	Offensive idea 2: National Conscripts Aymaran idea 7: Ayni Duties Prussian idea 6: Regimental Cantons Purépecha idea 4: War Bonfires	—	—
−5%	—	Lunda idea 4: An Army Overnight	—	—

There are also many modifiers from decisions, events and missions that affect recruitment time.

Provincial modifiers

	Conditions
+20%.0	for blockaded provinces
+30%.0	for looted provinces
+10%.0	for each point local unrest
−1%.0	per provincial tax income

Composition

See also: Battlefield unit deployment logic

To maximize combat effectiveness of an army, the ratio of infantry, cavalry and artillery is vital.

• To avoid the insufficient support penalty, an army must not surpass the maximum ratio of cavalry per infantry regiments.
• Artillery can fire from the second line, and therefore can vastly increase the effectiveness of an army.
• Artillery defends first line units from attacks with half of its defense points in the corresponding battle phase.
• Since artillery takes twice the normal damage when in the front line, it should be deployed in the second line. To achieve this, the number of artillery should not exceed the number of cavalry and infantry combined. Also reserves should be calculated to replace lost regiments in first line.
• With artillery being three times and cavalry two-and-a-half times more expensive than infantry, a more infantry heavy but cheaper army could be more cost-efficient, especially if a nation suffers from cavalry or artillery penalties. Eight infantry regiments can easily beat three infantry + two cavalry due to flanking effects.
• Having a 40 regiment army in a province with only 30 supply limit will cause massive attrition. It is wise to split an army in half when crossing territory with low supply limits in order to keep attrition at a minimum.

Example army relying on above information: (On plain terrain, with 11 combat width from technology and 15 base, 50% insufficient support limit)

+ 8 infantry, 5 cavalry reserves potentially not fielded if combat width too small

For Eastern/Western factions where there are few nation bonuses to cavalry combat effectiveness, cavalry should be fielded only to maximize flanking effectiveness. The number of cavalry should therefore change with flanking range at military technology 18 and 30. To understand why, consider that infantry begins with 1 flanking range and cavalry 2. This means that if you outnumber the enemy, there is only need for 2 cavalry units for the far-flanks as your infantry will flank one unit to the side. This dynamic changes at military technology 18 where infantry has 1 flanking range, but cavalry has 3. Here, a minimum of 4 cavalry units (2 on each side) is required. The dynamic changes for the last time at level 30, where 6 cavalry units will be required for maximize flanking.

For example:

• Early game: 8 infantry, 2 cavalry, 5 artillery

• Mid game: 18 infantry, 2 cavalry, 10 artillery

• Late game: 36 infantry, 4 cavalry, 20 artillery

• This rule does not apply to non-Eastern/Western nations who may have cavalry combat effectiveness bonuses and/or inferior infantry units compared to their Eastern/Western counterparts. Therefore, if you are playing Anatolian, Muslim or Nomadic factions and seek only combat effectiveness, field as many cavalry as the insufficient support limit allows.
• Fewer losses will be sustained with numerical superiority. When above 10:1, victory may be granted with no combat. To attain numerical superiority, it may require exceeding the supply limit temporarily, especially if forces are technologically inferior. By splitting forces, it is possible to lure an enemy into an unfavorable position without exceeding supply limits.
• When defending against a numerically superior army, fighting in terrain with an attacker combat penalty is ideal. Rough terrain gives from -1 to -2 combat penalty for the attacker and is added to river or strait crossing penalty and amphibious landing penalty.

Maintenance

An army needs a certain amount of money every month as maintenance. This cost can be influenced by the army maintenance slider of the economy interface. Reducing the maintenance slider can (multiplicatively) reduce maintenance cost by up to half, but also reduces reinforcement rates and morale. At 0% funding, regiments will not reinforce, and maximum morale will be reduced by 100% (additive with other percentage modifiers) to a minimum of 0.51 (the minimum required for an army to move).

Regiment maintenance cost

The maintenance cost (at a full maintenance slider) of a regiment is computed as follows:

${\begin{aligned}{\text{regiment maintenance cost per month}}=&\ 0.25\div 12\cdot \left({\text{regiment strength}}\right)\cdot \left({\text{base regiment cost}}\right)\cdot {\text{max}}\left(100\%+\sum {\text{regiment cost modifiers}},20\%\right)\\&\cdot \left(100\%+\sum {\text{land maintenance cost modifiers}}\right)\\&\cdot \left(100\%+0.02\cdot {\text{military technology}}\right)\end{aligned}}$

In other words, they cost about $0.25\div 12=2.08\%$ of their recruitment cost, multiplied by the sum of all maintenance modifiers, multiplied by the technology factor, per month. Therefore, any modifier that affects the cost of creating new regiments also affects the maintenance of units.

Maintenance cost modifiers

These modifiers affect the maintenance cost of land units and generally work additively, except for the maintenance impact of +2% per military technology, which is multiplicative with all other factors.

	Conditions
−25%	for having a native government type
−20%	from having 100% militarization (scales with militarization)
−20%	for being a march
−15%	for raising war taxes
−15%	for being the revolution target.
+10% / −10%	from nobility estates (scales with loyalty and influence))
−10%	for having a grand captain as advisor
−5%	for trading in salt
−10%	with parliament and “Quartering of Troops” as active issue
−10%	for having the reform “A Unified Army” as Mayan country (only with )
-10%	for having enacted the Misl Confederacy tier 1 government reform (only with )
-10%	for having enacted the Lip Service tier 3 tribal government reform.

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−10%	Adalite traditions Mantuan traditions	—	—	Administrative-Indigenous: Administration of Sacred Land Infrastructure-Horde: Gentle Conquest Act
−5%	Amago traditions Golden Horde traditions Lüneburger traditions Manchu traditions Munster traditions	Defensive idea 4: Regimental System Economic idea 6: Nationalistic Enthusiasm Quantity idea 6: The Old and Infirm Chosokabe idea 1: Ichiryo Gusoku Hanoverian idea 3: Schützenfest Horde idea 3: Horse Supplies Moroccan idea 6: Slave Soldiers Najdi idea 6: Unite the Tribes Nuremberger idea 2: Nuremberg Castle	Aq Qoyunlu ambition Arawak ambition Brunswicker ambition Chagatai ambition Mongolian ambition Nubian (minor) ambition Scottish ambition Tyrconnell ambition	Administrative-Quantity: Provincial Taxation System Economic-Quantity: Agricultural Cultivation

There are also many modifiers from decisions, events and missions that affect land maintenance modifier.

Total maintenance cost

See also: Force limit

The total maintenance cost of an army also depends on the land force limit of the country. If a country has more regiments than its land force limit, maintenance of all units will be multiplied by the ratio of units – with the units over the force limit counting twice – to the force limit. For example, if a country has 15 regiments and a land force limit of 10, the maintenance of each regiment is doubled.

Quality

While quantity is an important factor in warfare, quality is also significant.

Several idea groups can be taken to progressively improve armies' performance on the battlefield. Additionally, some countries get specific bonuses resembling the strength their army had in actual history.

Morale improvements

Morale indicates how long a single regiment can keep fighting without routing, making it a bit similar to HP (Health Points) in other games. It is affected by both prestige and power projection, which increase morale by +0.1% for every point.

Army morale

	Traditions	Ideas	Bonuses	Policies
+20%	—	Prussian idea 3: Army Professionalism	Sundanese ambition	—
+15%	Andalusian traditions Cascadian traditions Castilian traditions Eranian traditions Jerusalem traditions Nagpuri traditions Norse traditions Persian traditions Spanish traditions	Defensive idea 2: Military Drill Air idea 2: Cross of Agades Balinese idea 5: Conquerer Dalems Cirebonese idea 3: Ali's Panther Eora idea 6: Pemulwuy French idea 2: Lessons of the Hundred Years' War Great Qing idea 7: The Ten Great Campaigns Highlander idea 1: The Wallace Holy Roman idea 2: Kaiserliche Armee Iroquoian Federation idea 5: The Good Word Kiwi idea 6: Rejecting the Australia Constitution Lotharingian idea 2: Glory of Charlemagne Muskogean Federation idea 4: Valiant in War Polish idea 7: Focus on Field Defenses Revolutionary French idea 2: Elan! Siouan Federation idea 6: Until Death and After Vermont idea 1: Home of the American Revolution Veronese idea 4: Civil Blood and Civil Hands Zulu idea 5: Warrior Culture	Manchu ambition Swabian ambition Texan ambition	—
+10%	Anhalt traditions Aq Qoyunlu traditions Augsburger traditions Austrian traditions Austro-Hungarian traditions Ava traditions Beninese traditions Berber traditions Bruneian traditions Burgundian traditions Butua traditions Chernihiv traditions Client State traditions Corsican traditions Dalmatian traditions Deccani traditions Dhundhari traditions Dithmarscher traditions Gond traditions Hatakeyama traditions Hojo traditions Huron traditions Irish traditions Jurchen traditions Kamilaroi traditions Khorasani traditions Korean traditions Liège traditions Malayan traditions Moldavian traditions Mysorean traditions Nepalese Princedom traditions North Western Native traditions Oda traditions Ogasawara traditions Palawa traditions Pomeranian traditions Provençal traditions Punjabi traditions Rajputana traditions Rothenburg traditions Rûmi traditions Siamese traditions Sicilian traditions Somalian traditions Transoxianian traditions Trent traditions Tsutsui traditions Welsh traditions Zimbabwe traditions	Indigenous idea 4: Braves Plutocratic idea 2: Abolished Serfdom Adalite idea 6: Yahu Yahu Ajami idea 3: Legacy of the Ilkhans Amago idea 4: Ten Brave Warriors American Southwest idea 3: Raiding Nomads American idea 4: Lessons of Valley Forge Aragonese idea 7: Protect the Little Folk Ardabili idea 1: The Safavid Order Aymaran idea 5: The Tinku Rites Aztec idea 4: Eagles and Jaguars Bolognese idea 1: Etruscan Origins Brandenburg idea 4: Pomeranian Wars Bulgarian idea 6: Military Flexibility Carib idea 3: Resistance towards the Pailanti'po Catalan idea 6: 'Lliures o Morts' Cebu idea 1: Lumaya’s Ambition Chachapoyan idea 1: Warriors of the Clouds Charruan idea 6: Garra Charrua Cherokee idea 5: Ghigau Chiba idea 2: Dream of Masakado Creek idea 7: Red Sticks Daimyo idea 4: The Five Rings Desmondian idea 3: Gaelic Bastion Fijian idea 5: Fijian Warlords Finnish idea 7: The Anjala Conspiracy French Ducal idea 7: La Petite Nation Frisian idea 3: Dutch Courage Fulani Jihad idea 4: Imams and Emirs Galician idea 5: Santiago y Cierra! Garhwali idea 3: Martial Diplomacy Gelre idea 5: The Gelderland Wars Genevan idea 7: Armed Neutrality Goslar idea 6: Resisting the Welfs Great Shun idea 4: Obedient to Heaven Great Yuan idea 2: A Savage Kingdom Holy and Enchanted Herzegovinian idea 3: Stjepan's Rebellion Hisn Kayfan (Ayyubid) idea 3: Righteousness of the Faith Hisn Kayfan idea 3: Righteousness of the Faith Imerina idea 2: The Twelve Sampys of Imerina Ionian idea 1: Frankokratia Israeli idea 7: The Chosen People Iwi idea 4: Kapa Haka K'iche idea 6: K'iq'ab's Vengeance Kangra idea 3: Martial Heritage Khmer idea 1: Preah Ko Preah Keo Kikuchi idea 4: Fortify the Domain Kildarean idea 3: Silken Thomas Krakowian idea 1: Legendary Legacy Lanfang idea 4: National Militia Livonian idea 2: Border between East and West Luban idea 4: Encourage the Kasala Tradition Lur idea 6: Rise of the Lurs Lüneburger idea 7: Lionhearted Mainzian idea 3: Weck, Worscht & Woi Majapahit idea 5: Gajah Mada's Oath Manipur idea 2: Martial Traditions Mayan idea 7: Caste War Medri Bahri idea 5: Independent Traditions Mexican idea 7: Grito de Dolores Miao idea 3: Unity of the tribes Mindanao idea 6: Guerrilla Warfare Muscovite idea 4: Pomestnoe Voisko Mushasha idea 1: Fervent Millenarianism Nanbu idea 1: Genji in the North Native idea 1: Counting Coups Neapolitan idea 4: Crush the Power of the Barons Nepali idea 5: The Royal Kumari Nivernais idea 4: True Frenchmen Northeastern Woodlands idea 5: Marten Clan Orleanaise idea 2: The Maid of Orleans Pegu idea 4: Ramannadesa Perugian idea 6: The War of the Eight Saints Rassid idea 1: The Living Imam Sadiyan idea 1: Land of Glory Saluzzo idea 3: Marquisate Samtskhe idea 4: Independent Ambitions Sardinian idea 1: From the Judicate Semien idea 1: Legacy of Queen Judith Serbian idea 7: Balkan Hajduks Shiba idea 4: Atsuta Shrine Shimazu idea 1: Satsuma Hayato Shoni idea 2: Defender of Japan Slovak idea 7: Slovak National Awakening Songhai idea 3: Jihad Against the Pagans Swabian City-State idea 3: Bavarian Resistance Takeda idea 1: Leader of Kai Genji Three Leagues idea 4: The League of Ten Timurid idea 2: The Mantle of the Great Khan Tiwi idea 6: Tiwi Isolationism Tokugawa idea 1: Mikawa Bushi Trebizond idea 5: The Lessons of the Fourth Crusade Uesugi idea 4: Dragon of Echigo Yarkandi idea 5: Holy Warriors Yi idea 7: Children of the Black Tiger	Ajuuraan ambition Athenian ambition Brabant ambition Circassian ambition Colonial ambition Cornish ambition Dai Viet ambition Frankfurter ambition Kievan ambition Kitabatake ambition Pueblo ambition Ryazan ambition	Divine-Religious: Wielders of the Flaming Sword Indigenous-Exploration: War on Our Terms Mercenary-Religious: Dutiful Mercenaries Act Religious-Quantity: Field Priests and Soldier's Prayer Books
+5%	—	Chagatai idea 2: Ceaseless Border Wars Russian idea 7: Broaden the curriculum of the Cadet Corps	—	Horde-Influence: Kharash Indigenous-Economic: The Three Sisters

Morale recovery improvements

Morale recovery affects how long an army will take to recover to full morale after it was lost in a battle or by changing the maintenance slider.

Army morale recovery

	Traditions	Ideas	Bonuses	Policies
+15%	—	—	—	Expansion-Defensive: Local Army Organization Mercenary-Expansion: Hired Expeditions Act Quality-Administrative: The Liquor Act
+10%	Armenian traditions Fulani traditions Great Armenian traditions Montferrat traditions Ryazan traditions	Pskovian idea 2: Legacy of Daumantas	Fully Offensive Persian ambition	Divine-Administrative: Omne Datum Optimum
+5%	—	—	—	Religious-Quantity: Field Priests and Soldier's Prayer Books

Discipline improvements

Discipline is a very important combat modifier, as it affects the offensive capabilities of your armies, while also indirectly boosting their defensive capabilities by increasing your Military Tactics.

Discipline affects both physical and morale casualties that your armies deal and take.

	Traditions	Ideas	Bonuses	Policies
+5.0%	Aksumite traditions Anatolian traditions Asakura traditions Couronian traditions Finnish traditions Imagawa traditions Japanese traditions Knights Hospitaller traditions Latin traditions Livonian traditions Nanbu traditions Ottoman traditions Roman traditions Romanian traditions Scandinavian traditions Shawnee traditions Teutonic traditions Three Leagues traditions Wallachian traditions	Offensive idea 7: Esprit de Corps Ando idea 6: True Shogun of Oshu Angevin idea 3: Lessons of the Anglo-French Wars Austrian idea 7: Hofkriegsrat Austro-Hungarian idea 1: Imperial and Royal Army Bavarian idea 6: Found a Professional Army Bharathi idea 4: Indian Army Bregenzer idea 1: Lady of Bregenz British idea 5: Reform of Commission Buying Brunswicker idea 7: The Black Brunswickers Burgundian idea 4: Reform of the Feudal Army Butua idea 5: Regular Training Byzantine idea 6: The Strategikon Candarid idea 5: Legacy of the Candar Corps Chosokabe idea 4: 100 Article Code Colognian idea 7: Order of St. Michael Dahomey idea 5: The Amazons Daimyo idea 1: Bushido Deccani idea 5: Modernize the Sarf-e-Khas Divine idea 1: Holy Order Epirote idea 7: Unity in Strength French idea 6: Europe's First Standing Army Great Ming idea 2: Revive the Three Grand Divisions Great Moravian idea 7: Svatopluk's Legacy Hessian idea 5: Modernization of the Hessian Army Holy Roman idea 6: Adopting the Goosestep Hungarian idea 3: Found the Black Army Icelandic idea 5: The Men of Fire and Ice Imperial German idea 3: Reichsheer Irish idea 7: Nationalized Gallowglass Septs Iroquois idea 6: Warriors Unity Israeli idea 2: National Myths Restored Jerusalem idea 3: Frontier State Kaffan idea 6: King of Kings Kangra idea 7: Tigers of the Himalayas Khmer idea 5: European Mercenaries Kongo idea 7: Defend Against the Colonists LPC idea 2: Tempered by Neighbors Livonian Knight idea 1: Livonian Brothers of the Sword Lübeckian (Hansa) idea 3: Reform the Queen's Army Malian idea 4: Mandinka Warrior Spirit Mamluk (upgraded) idea 5: Reform of the Army Mamluk idea 5: Reform of the Army Mantuan idea 5: Soldiers for Protection Mapuche idea 2: Clava Clubs Mewari idea 7: Reorganized Rajput Regiments Mughal idea 1: The Jagir and Mansabdari Systems Munster idea 4: Spanish Ties Mutapan idea 1: Mwenemutapa Münster idea 5: Soldiers from the Imperial Armies Navarran idea 3: Basque Ferocity Nubian idea 4: Military Strength Oirat idea 6: Defiance of the Dzungars Otomo idea 3: Loyal Retainers PLC idea 7: Tempered by Neighbors Persian idea 3: Found the Ghilman Polish idea 6: Found the Foreign section Punjabi idea 7: Reforming the Punjabi Army Rigan idea 7: Restore the Brothers of the Sword Rothenburg idea 5: The Drink of War Rûmi idea 1: Abul-Fath Sardinian idea 7: The Order of Saint Maurice Sardinian-Piedmontese idea 4: Royal Sardinian Army Saxon idea 7: The Saxon Circle Shimazu idea 4: Tsurinobuse Southeastern Woodlands idea 7: Stomp Dancers Swedish idea 2: Swedish Steel Tibetan idea 6: The Way of the Ancients Tokugawa idea 3: Hatamoto Uesugi idea 6: Agakita-shu United Crowns idea 1: Reform of Commission Buying Vijayanagar idea 7: An Army for the City of Victory	Full Quality Adalite ambition Amago ambition Ambition of Theodoro Ansbach ambition Bamberger ambition Banteni ambition Bayreuther ambition Carib ambition Dortmund ambition Ethiopian ambition Franconian ambition Hanoverian ambition Hindustani ambition Hisn Kayfan (Ayyubid) ambition Hisn Kayfan ambition Karamanid ambition Lüneburger ambition Manx ambition Mysorean ambition Nepali ambition Ogasawara ambition Papal ambition Prussian ambition Rajput ambition Rajputana ambition Ruthenian (minor) ambition Ruthenian ambition Siamese ambition Songhai ambition Spanish ambition Swiss ambition Timurid ambition Trierian ambition Tuscan ambition Vermont ambition Westphalian ambition Yamana ambition Zulu ambition	Economic-Quality: Weapon Quality Standards
+2.5%	—	Incan idea 4: Drafted Hatun Runas National idea 1: Preserve Our Troops Norwegian idea 7: Write New Sagas	—	Indigenous-Exploration: War on Our Terms

Combat ability improvements

Combat ability is a value that is multiplied with the units' damage dealt (both for casualties and morale).

Infantry combat ability

	Traditions	Ideas	Bonuses	Policies
+20%	Swedish traditions	Prussian idea 5: The Goose Step Scandinavian idea 6: Swedish Caroleans	—	—
+15%	Imperial German traditions	Dalmatian idea 5: Dalmatian Independent Army Great Shun idea 6: From Sticks to Guns Hindustani idea 1: Sepahi Italian idea 2: The Tradition of the Legion Livonian idea 1: Legacy of the Knights PLC idea 6: The Polish Royal Guards	Bulgarian ambition Japanese ambition Norse ambition Three Leagues ambition	Innovative-Quality: Modern Firearm Techniques
+10%	Ashanti traditions Aztec traditions Beloozero traditions Bengal Sultanate traditions Bengali traditions Chosokabe tradition Date traditions English traditions Georgian traditions German traditions Gujarat Sultanate traditions Hosokawa traditions Iroquois traditions Lanfang traditions Lotharingian traditions Lur traditions Malvi traditions Mewari traditions Milanese traditions Mindanao traditions Mushasha traditions Oda traditions Portuguese traditions Québécois traditions Rassid traditions Saluzzo traditions Shimazu traditions Slovak traditions Songhai traditions Swiss traditions Tokugawa traditions Tripuran traditions Tyrone traditions Veronese traditions Vijayanagar traditions Yemeni traditions Zambezi traditions	Mercenary idea 6: Seasoned Veterans Quality idea 1: Private to Marshal Ainu idea 7: Fierce Resistance Amago idea 2: Izumo Shugo Angevin idea 5: Reformed Angevin Infantry Arawak idea 5: Arawak Raiders Asakura idea 4: Asakura Soteki Australian idea 4: The Diggers Bohemian (upgraded) idea 3: Wagenburg Bohemian idea 3: Wagenburg Brandenburg idea 1: Northern March Brazilian idea 4: Halting Foreign Incursions Butua idea 3: Empowering the Rozwi Carib idea 2: Poisonous Warfare Caspian idea 2: A Time of Turmoil Chickasaw idea 2: Spartans of the Lower Mississippi Chinese idea 5: Firearm Training Croatian idea 7: Pandurs Dai Viet idea 1: The Great Proclamation Deccani Sultanate idea 4: Purchase Habshis Dithmarscher idea 1: Resistance to Feudalism Eastern Algonquian idea 6: White-Tialed Deer French Ducal idea 3: Qui Ruit Et Lethum Galician idea 7: Irmandinos Garjati idea 5: Jungle Warfare Gond idea 5: Raiding the Lowlands Greek idea 3: Klephtic Recruitment Guarani idea 7: Royal Armaments Horn of African idea 4: Oromo Warriors Interlacustrine idea 6: Unity of the Clans Jaunpuri idea 7: Modernization of the Army Laotian idea 5: Laotian Elephant Cavalry Leonese idea 7: Leonese Nationalism Livonian Knight idea 7: Military Reforms Maravi idea 5: Serving Abroad Nepali idea 6: The Gurkhas Orissan idea 1: Lord of the Elephants Ormond idea 1: English Service Polish idea 3: Piechota Wybraniecka Purépecha idea 1: Copperworking Roman idea 4: The Roman Legions Sadiyan idea 6: Reform the Sadiya Armies Satake idea 4: Kashima Jingu Shiba idea 7: Mogami Family Somali idea 4: Offensive Warfare Teutonic idea 3: Adjust our Infantry Tactics Tsutsui idea 1: Warrior Monks Tupi idea 3: It Is A Good Day To Die Tverian idea 6: Tverian Tercio Zulu idea 3: The Impi Warriors	Deccani ambition Imerina ambition Indian Sultanate ambition Kitaran ambition Korean ambition Malian ambition Mantuan ambition Mayan ambition Montenegrin ambition Nepalese Princedom ambition Nivernais ambition Polotskian ambition Serbian ambition Sistani ambition Uesugi ambition	—
+5%	—	Athenian idea 7: Athenian Army Reform Kongo idea 5: The Triangle Trade Ryazan idea 5: March of Russia Tunisian idea 1: Catalan Guard	—	—

Cavalry combat ability

	Traditions	Ideas	Bonuses	Policies
+30%	—	PLC idea 4: Winged Hussars Polish idea 4: Winged Hussars	—	—
+25%	—	LPC idea 5: Lithuanian Hussars Lithuanian (upgraded) idea 5: Lithuanian Hussars Lithuanian idea 5: Lithuanian Hussars United Arabian idea 1: Arabian Horseman Tactics	Full Horde ideas	—
+20%	Aq Qoyunlu traditions Bukharan traditions Chagatai traditions Great Yuan traditions Hungarian traditions Ilkhanid traditions Mughal traditions Oirat traditions Qara Qoyunlu traditions	Burmese idea 2: Elephant Warfare Crimean idea 1: Genghisid Legacy Eranian idea 4: Reform the Savaran Cavalry Golden Horde idea 3: Tatar Traditions Horde idea 2: Traditions of the Great Khan Kazani idea 3: Warrior Society Mongolian idea 1: Ghostly Horses of the Plain Transoxianian idea 1: Mawarannahr, the land Beyond the River	—	—
+15%	Ayutthayan traditions Delhian traditions Khorasani traditions Persian traditions	Aristocratic idea 1: Noble Knights Afghan idea 5: Durrani Imperialism Anatolian idea 3: Akîncî Cavalry Ansbach idea 7: Dragoons of Ansbach Ardabili idea 2: The Qizilbash Bharathi idea 1: Modernized War Elephant Tactics Chernihiv idea 2: Field Cossack Regiments Couronian idea 7: Promote the Curonian Kings Epirote idea 5: Latin Knights Finnish idea 2: The Hakkapeliitta Karamanid idea 3: Karamanid Cavalry Khivan idea 1: Horde Legacy Lan Xang idea 2: Elephant Cavalry Latin idea 5: Latin Knights Manchu idea 5: Link with the Mongol Dynasty Maratha idea 1: Tradition of Military Service Ottoman idea 3: Timar System Rajput idea 3: Marwari Horses Rajputana idea 3: Marwari Horses Ruthenian (minor) idea 3: Zaporozhian Cossacks Ruthenian idea 3: Zaporozhian Cossacks Serbian idea 4: Alemannic Guard Shirvani idea 3: Tribesmen of the Caucasus Siamese idea 2: Advanced Elephant Warfare Transylvanian idea 1: Unio Trium Nationum	Ava ambition Hejazi ambition	—
+10%	Al-Haasa traditions Bahmani traditions Bavarian traditions Croatian traditions Deccani Sultanate traditions Indian Sultanate traditions Mamluk (upgraded) traditions Mamluk traditions Mazovian traditions Mossi traditions Northumbrian traditions Takeda traditions Teutonic traditions	Quality idea 3: Finest of Horses Adalite idea 4: Mujahidun Cavalry Berber idea 5: Tuareg Cavalry Caucasian idea 7: Cavalry Armies Franconian idea 4: Free Imperial Knights of Franconia Gujarati Princedom idea 1: Kathiawari Horses Hisn Kayfan (Ayyubid) idea 4: Elite Warriors Hisn Kayfan idea 4: Elite Warriors Kildarean idea 5: Curragh Horsemanship Moroccan idea 6: Slave Soldiers Nubian (minor) idea 6: Desert Cavalry Oyo idea 5: The Oyo Cavalry Sukhothai idea 7: War Elephants Vijayanagar idea 2: Arab Horses Wurzburgian idea 3: Franconian Circle	Charruan ambition Punjabi ambition Vindhyan ambition	Aristocratic-Espionage: Noble Loyalty Act Horde-Espionage: Psychological Warfare
+5%	—	Circassian idea 1: Horsemen of the Steppe Ogasawara idea 3: Kiso-uma	—	—

Artillery combat ability

	Traditions	Ideas	Bonuses	Policies
+10%	—	Quality idea 7: Massed Battery Adalite idea 7: Embrace the Cannons Austro-Hungarian idea 7: The Future of Warfare Bharathi idea 7: Develop Rocket Technology Ferraran idea 3: Alfonso I's Reforms Russian idea 3: Russian Artillery Yard Smolenskian idea 6: Artillery Before All	Otomo ambition Satake ambition	Offensive-Economic: Horse Artillery
+5%	—	Athenian idea 7: Athenian Army Reform	—	—

General improvements

These modifiers affect the base attributes of the military leader and are added on top of them.

Land leader shock

	Traditions	Ideas	Bonuses	Policies
+1	Manchu traditions Qara Qoyunlu traditions Scottish traditions Shirvani traditions Timurid traditions	Offensive idea 1: Bayonet Leaders Ajuuraan idea 6: Expelling the Infidel Aq Qoyunlu idea 1: The White Sheep Arawak idea 7: Jungle Warfare Bengal Sultanate idea 5: Conquest of the Gangetic Plain Charruan idea 3: Bolas Warfare Chiba idea 5: Katori Jingu Cilli idea 2: Mercenary Captains Crimean idea 4: Despoilers Epirote idea 1: Legacy of Pyrrhus Hatakeyama idea 2: Indomitable Generals Hojo idea 2: Night Combat Horde idea 4: Steppe Leaders Iwi idea 6: Te Moko Jerusalem idea 5: Crusader Aristocracy Jurchen idea 3: Foreign Service LPC idea 1: Warlord Dukes Lithuanian (upgraded) idea 1: Warlord Dukes Lithuanian idea 1: Warlord Dukes Mexican idea 6: Heroes of the Revolution Mongolian idea 7: The Kheshig Norse idea 3: A Wall of Shields for the King Oda idea 3: Oda Generals Rassid idea 6: Like Salt Dissolves in Water Shan idea 5: Raiders Shoni idea 5: Bear of Hizen Tibetan idea 2: Bön Influence. Tyrconnell idea 5: Lessons of Knockavoe Wallachian idea 5: Legacy of the Impaler Yamana idea 4: The Western Army	Air ambition Arabian ambition Oirat ambition Swedish ambition Tiwi ambition	Humanist-Quantity: Inspirational Leaders

Land leader fire

	Traditions	Ideas	Bonuses	Policies
+1	—	Offensive idea 3: Superior Firepower Great Ming idea 7: The Red Cannon Rajput idea 6: Martial Ethos Smolenskian idea 5: Hold The Line	Bohemian (upgraded) ambition Bohemian ambition Mori ambition Oda ambition Qara Qoyunlu ambition Utsunomiya ambition	Expansion-Quality: The Mining Act

Land leader maneuver

	Traditions	Ideas	Bonuses	Policies
+2	—	Evenk idea 6: Love of the Forest	Shawnee ambition	—
+1	Ainu traditions Burmese traditions Carib traditions Crimean traditions Herzegovinian traditions Norman traditions Ulmer traditions	Defensive idea 3: Improved Maneuver Air idea 6: Nomadic Traditions Albanian idea 2: Land of Ambushers Arabian idea 6: Clan Loyalties Brabant idea 2: Marsh Warfare Caucasian idea 3: Hit and Run Kazani idea 5: Steppe Warfare Mongolian idea 6: Mongolian Mobility Nagpuri idea 2: Exploit Harsh Terrain North Western Native idea 6: Canoe People Oirat idea 1: Fearsome Warriors of Tumu Permian idea 5: Warriors of the Taiga Qara Qoyunlu idea 4: Dynamic Warfare Romanian idea 2: Skilled Commanders Tapuian idea 5: The Way of the Jaguar Tyrone idea 6: Ambush Warfare Zaporozhian idea 4: Hit And Run	Lithuanian (upgraded) ambition Lithuanian ambition	Quantity-Exploration: Hired Adventurers

Leader siege

	Traditions	Ideas	Bonuses	Policies
+1	—	Nepali idea 7: Envelopment and Blockade Oda idea 4: Influential Strongholds	Full Aristocracy Cilli ambition Meath ambition Sonoran ambition Urbinate ambition	Innovative-Offensive: Modern Siege Weapons

Army tradition

Main article: Military tradition#Army tradition

Army tradition provides powerful boons to the offensive power of armies. It also provides a higher chance of getting great land leaders by increasing the number of pips they can get. 100 army tradition gives the following bonuses, which scale linearly to 0% at 0 tradition.

At 100:

	+10%.00	Recover army morale speed
	+25%.00	Morale of armies
	+10%.00	Manpower recovery speed
	+5%.00	Siege ability
	+0.10%	Commanderies faction influence
	+0.10%	The aristocrats influence
	+0.10%	Girondists influence
	+0.10%	Militarization of state
	+5%.00	Nobility loyalty equilibrium
	+5%.00	Marathas loyalty equilibrium
	+5%.00	Rajputs loyalty equilibrium

Supply and attrition

In EU4, the word "attrition" indicates the loss of manpower due to insufficient supply. This use of the word "attrition" is different from Paradox Interactive's other game, Hearts of Iron IV, where "attrition" indicates equipment loss, but not manpower loss. In EU4, Army attrition is manpower loss.

An army will take attrition damage on the first day of each month if the total supply weight of all non-hostile armies in the province exceeds the supply limit of that province. This can happen even in owned provinces. The amount of attrition depends on the supply weight of all troops in that province in comparison to the local supply limit.

Supply weight

Each regiment in an army has a supply weight of 1. The total supply weight of an army with a leader is reduced by 1 for each point of maneuver the leader has. Province modifiers that increase attrition act by increasing the supply weight of each army in addition to increasing attrition. The final attrition damage for an army is determined by this formula:

${\text{attrition (}}\%{\text{)}}=\left({\frac {\#{\text{ of troops}}}{1000}}+{\text{Unit Weight attrition modifiers}}-{\text{TRUNC(supply limit)}}\right)\cdot {\frac {10}{\text{TRUNC(supply limit)}}}+{\text{province attrition modifiers}}$

where

${\text{supply limit}}=({\text{base}}+{\text{terrain bonus}})\cdot (1+{\text{supply limit efficiency}})$

The only exception to this is if an army has moved into a province where two hostile forces are engaged in combat. As the combatants are temporarily neutral to the newly arrived army, some of their supply weight will still be added to this armies' and may cause attrition.

Supply limit

The base supply limit of each province depends on the terrain type:

Source	Supply limit
Base	+6
Farmlands	+10
Grassland	+8
Drylands	+7
Coastline	+6
Highlands	+6
Savannah	+6
Steppes	+6
Woods	+6
Hills	+5
Jungle	+5
Marsh	+5
Coastal Desert	+4
Desert	+4
Glacier	+2
Mountains	+4
Forest	+4

This is then adjusted by supply limit efficiency modifiers. All modifiers below stack additively:

Amount	Source
+50%	Province is coastal
+50%	Area of the province has a supply depot
+25%	Owner of province
+10%	Military Access/Allied/Controlled/Cored Enemy Province
+2%	Per development level
up to −50%	Proportional to the level of devastation
−20%	Arid climate
−30%	Tropical climate
−40%	Arctic climate
−10%	Mild winter
−20%	Normal winter
−30%	Severe winter
−10%	Mild monsoon
−20%	Normal monsoon
−30%	Severe monsoon
+50%	Military technology level 5
+50%	Military technology level 12
+50%	Military technology level 17
+50%	Military technology level 19
+50%	Military technology level 27
+50%	Military technology level 31

The Quantity idea 5: Camp Followers, and Somalia idea 5: The Blue Nile increases the national supply limit by 33%.

Attrition damage

Under normal circumstances, the amount of attrition is x%, where x is 10/supply limit, for each point of supply weight in excess of the local supply limit, up to the maximum attrition amount (normally 5%). Armies that are besieging hostile provinces take 1 unit of supply weight extra attrition, regardless of their size. An army trying to take back its own captured province does not suffer this penalty. For the duration of a battle, the armies engaged do not suffer attrition.

Example: An army with 20 supply weight in a province with 17 supply limit would normally take (20 - 17)*(10/17) = 1.76% attrition each month. If that army were besieging a hostile province it would suffer (20 + 1 - 17)*10/17 = 2.35% attrition.

Besieging armies will always take at least 1% base Attrition attrition, even if the province is unfortified. This rule only applies to enemy-owned provinces, however - when besieging friendly provinces to retake them from the enemy, this rule is ignored.

Attrition damage is applied before reinforcements, so an army suffering from attrition will not take noticeable damage unless the attrition exceeds the reinforcement rate. This can mask an otherwise severe drain in manpower due to attrition, so players are advised to pay careful attention to any army with the attrition icon (). The attrition damage taken by a unit is proportional to the current strength of the unit and not the maximum strength of the unit.

At sea

Aside from Marines, units on board transports will take a monthly Naval Attrition rate of 1% in coastal waters and 10% in open seas.

Attrition modifiers

Climates that increase attrition according to the in-game tooltips act by increasing each army's supply weight instead. Devastated provinces will also increase local attrition rates. Attrition stacks additively.

Arctic	−40%	+1%
Tropical	−30%	+2%
Arid	−20%	+1%
Mild Winter	−10%	+1%
Normal Winter	−20%	+2%
Severe Winter	−30%	+3%
Devastation	Up to −50%
General Maneuver Pips	−(1-6)

The 7th idea of the Defensive Ideas group, Improved Foraging, reduces all attrition taken by friendly armies by 25%, applied multiplicatively. For example, an army under the supply limit with Improved Foraging besieging an enemy province takes 0.7% monthly attrition. It would make sense for the attrition to be 0.75% monthly, but the attrition display indicates 0.7%. The bonus for completing the Defensive Ideas group causes enemy troops to take 1% attrition on top of normal attrition values while in friendly territory.

Ideas which reduce attrition are applied after reaching the attrition cap, so an army with -25% attrition damage has an effective maximum attrition of 4%.

Unique national ideas, idea groups, and policies which affect land attrition:

	Traditions	Ideas	Bonuses	Policies
−25%	—	Quantity idea 7: Expanded Supply Trains Fijian idea 6: Kai Colo	—	Humanist-Defensive: The Preparation Act Quality-Exploration: Superior Supply Systems
−20%	Kongo traditions	Horde government idea 4: There Shall Be No Grass Cascadian idea 7: The Oregon Trail Horde idea 1: The Life of a Steppe Warrior Mongolian idea 3: The Life of a Steppe Warrior Oirat idea 2: The Life of a Steppe Warrior Siouan Federation idea 3: Between the Rivers	—	Innovative-Divine: Ora et Labora
−15%	Ainu traditions Arabian traditions Canadians traditions Siberian traditions	Charruan idea 2: Legacy of the Pampas Cossack idea 3: Steppe Riders Dhundhari idea 7: Pindari Mercenaries Vereenigde Oostindische Compagnie idea 6: Into Foreign Lands Zaporozhian idea 3: Steppe Riders	—	—
−10%	Ethiopian traditions Karelian traditions Khivan traditions Kongolese traditions Malian traditions	Aboriginal idea 4: People of the Outback Australian idea 2: The Land Down Under Aymaran idea 3: Chu'uqi Production Banteni idea 5: Fertile Lands Burmese idea 6: Organized Military Campaigns California Native idea 7: Ceremonial People Chagatai idea 1: The Mountain Khanate Clanricarde idea 5: To Hell or to Connacht Evenk idea 1: Family Brigades Hejazi idea 4: Desert Warfare Incan idea 7: Tambo Waystations Montferrat idea 3: The Italian Frontier Nubian idea 3: Desert Knowledge Plains Native idea 3: Bison Hunters Sami idea 6: Living off the Land Southeastern Woodlands idea 4: Cultivation of the Earth Tapuian idea 1: Hunter Gatherers Texan idea 4: Vaqueros	Chickasaw ambition Jurchen ambition	Indigenous-Espionage: Indirect Approach

Land attrition is capped at −90%, resulting in 1% maximum attrition.

The Great Wall of China great project also gives a maximum of 2% attrition with an accepted Chinese culture group

Additionally, there are ideas that give a malus to attrition to enemies on a nation's territory:

	Traditions	Ideas	Bonuses	Policies
+1.0	Brazilian traditions Caucasian traditions Dai Viet traditions Evenk traditions Garhwali traditions Icelandic traditions Interlacustrine traditions Kangra traditions Kongolese traditions Leinster traditions Luban traditions Lunda traditions Mapuche traditions Montenegrin traditions Northumbrian traditions Nubian traditions Offaly traditions Ogasawara traditions Polotskian traditions Sadiyan traditions Tripuran traditions Tumbuka traditions Welsh traditions	Indigenous idea 2: Irregular Warfare Afghan idea 7: Graveyard of Empires Ainu idea 5: Hunters and Warriors American Southwest idea 6: Into the Desert Assamese idea 3: River Warfare Australian idea 2: The Land Down Under Baluch idea 1: Natural Defenses Beloozero idea 6: Boreal Warfare Berber idea 2: Desert Warfare Bosnian idea 7: Over the Hills and Through the Woods Carib idea 4: Rainforests of the Guyana Chachapoyan idea 7: Cloud Forests Charruan idea 5: Resist Conquistadors Chickasaw idea 3: Nighttime Raids Cornish idea 2: Cornish Rebels Divine idea 6: Turn the Other Cheek Eastern Algonquian idea 3: Slash and Burn Agriculture Finnish idea 6: The White Death Flemish idea 7: Noose-Bearers Gond idea 3: Tigers and Elephants Hadramhi idea 1: Death Has Come Highlander idea 2: The Highland Clans Jurchen idea 1: Sons of the Mountain Khivan idea 2: Deserts of Khiva Kuban idea 5: Ngesh Dancing Kurdish idea 1: Mountain Warriors Lanfang idea 4: National Militia Ligori idea 5: Bridge to Siam Lusatian idea 1: Zittau Mountains Luzon idea 2: Conquest of Paradise Mayan idea 6: Remote Isolation Miao idea 6: Mountain Retreats Munster idea 3: Hill Raiders Mushasha idea 3: Swamp Warfare Najdi idea 4: Bedouin Raiders Nubian (minor) idea 3: Warriors of the Sahara Desert Romanian idea 3: Scorch the Lands and Poison the Wells Sami idea 1: Land of the Midnight Sun Shawnee idea 2: Dark and Bloody Ground Siberian idea 1: Hunters of the North Sinhalese idea 7: Sinhalese Guerrilla Warfare Sulawesi idea 7: Asymmetrical Resistance Tirhuti idea 5: Riverine Landscape Tsutsui idea 4: Mountain Warfare Ulster idea 4: Rapparees Vindhyan idea 5: Untamed Lands Yi idea 2: Deep in the Mountains Zimbabwe idea 5: Lay of the Land	Fully Defensive Armenian ambition Great Armenian ambition Moroccan ambition Siouan ambitions Southeastern ambitions	Defensive-Religious: Edict of Resistance Influence-Quantity: Guerrilla Warfare Infrastructure-Defensive: Bolstered Defence Act
+0.5	—	Chagatai idea 1: The Mountain Khanate Trierian idea 4: Landesburgen	—	—

By default, the maximum attrition an army can suffer is 5%. This amount for enemies can be increased by the following:

- The Righteous Army decision for Korea (enabled with Righteous Army government reform): +3

- Reward for White Death Upon Europe mission for Finland: +1

- Tier 3 government reform Defensive Stance: +1

- Tier 3 government reform Reinforce the Sygnakhs: +1

- Defensive ideas finisher: +1

- Incan ambitions: +1

Reinforcements

Army regiments that have taken casualties will gradually reinforce up to their full strength according to available manpower, or if they are mercenaries - usually at a significant cost. However, if they gain more soldiers monthly than they lose to attrition, there is no extra cost beyond base army maintenance, so reinforcement speed modifiers can save you a lot of money - even so, beware of heavy attrition.

Reinforcement speed

The number of reinforcements that each regiment can receive in a month is:

${\text{reinforcements per month}}=100\ \cdot \ {\text{army maintenance factor}}\ \cdot \ {\text{local reinforcement modifier}}\ \cdot \ \left(100\%+\sum {\text{global reinforcement modifiers}}\right)$

Army maintenance factor

The army maintenance factor scales linearly with the position of the army maintenance slider. It is 50% if the slider is at the far left and 100% if the slider is at the far right.

Local reinforcement modifier

The local reinforcement modifier is 100% in owned provinces, 10% in uncolonized provinces, and 50% otherwise, be it a neutral, subject, ally, enemy, or occupied province. If the army has a leader, each point of maneuver will increase the local reinforcement modifier by +10% additively up to a maximum of 100%. An army that has been in battle will suffer a temporary −40% penalty to their local reinforcement modifier for the current month if they are not in owned territory.

Global reinforcement modifiers

The reinforcement speed modifiers from ideas, policies, advisors etc. are summed up.

Reinforce speed is affected by the following:

	Conditions
+33%	with a quartermaster as advisor
+33%	with a general with 'Battlefield Medic' trait
+25%	"Organized Military Staff" Tier 5 common government reform
+25%	"Sekban Recruitment" Tier 5 common government reform for Ottomans
+25%	"Staatse Leger" Tier 5 common government reform
+25%	New Military Manual "Prussian Monarchy" Tier 1 Monarchy government reform interaction for Prussia
+20%	"Maratha Army" Tier 5 common government reform
+20%	Mobilized new Order Regiments "Russian Empire" Tier 1 Monarchy government reform interaction for Russia
+20%	Mobilized new Order Regiments "Great Russian Federation" Tier 1 Republic government reform interaction for Russia
+15%	"Nizam-i Cedid" Tier 11 Monarchy Government reform for Ottomans and Rûm
−25%	is bankrupt

For special unit regiments:

	Conditions
+50%	Cawa regiments
+33%	Mamluk regiments
+33%	Janissary regiments with "Loosen Devshirme System" Janissaries estate privilege
+25%	Tercio regiments after the Spanish mission "Refine the Tercios"
+10%	Streltsy regiments with the "Establish the Streltsy" Tier 4 common government reform
−50%	Banner regiments
+33%	Banner regiments with "Eight Banners" Tier 5 common government reform

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
+30%	—	Defensive idea 6: Supply Trains Austrian idea 7: Hofkriegsrat	—	—
+20%	—	—	—	Infrastructure-Quantity: Mass Conscription Act
+15%	Serbian traditions Yaroslavlyian traditions	American Southwest idea 2: Four Clans Yi idea 3: Chain of Zimo Domains	Tverian ambition	Espionage-Quality: The Deserter Act Quality-Administrative: The Liquor Act
+10%	Muskogean traditions Tupi traditions	Québécois idea 6: Commissions for Noble Sons	Khivan ambition	—
+5%	—	Siberian idea 6: Successful Raids	—	—

All values above can be seen or deduced from the tooltip over each army's total soldier count.

Reinforce cost

${{\text{reinforcement cost}}=0.4\cdot {\frac {\text{arriving base reinforcements}}{1000}}\cdot {\text{base regiment cost}}\cdot {\text{max}}\left(100\%+\sum {\text{regiment cost modifiers}},20\%\right)\cdot \left(100\%+\sum {\text{reinforcement cost modifiers}}\right)\cdot \left(100\%+2\%\cdot {\text{military technology}}\right)}$

• The base reinforcements are up to 100 per Regiment, depending on army status and location.
• Additional reinforcements from reinforcement speed modifiers don't cost extra ducats, but still consume additional manpower.
• Reinforce cost is capped at 10% (it can't be reduced more than -90%).

Ideas and policies:

	Traditions	Ideas	Bonuses	Policies
−33%	—	Quantity idea 5: Salvage our Equipment	—	—
−25%	—	Uesugi idea 3: Kamakura Office	—	Influence-Offensive: Foreign Conscription Centers
−20%	—	—	—	Infrastructure-Quantity: Mass Conscription Act
−15%	—	Mongolian idea 5: Yams of the Great Khan	—	—

Army professionalism and drilling

Cradle of Civilization introduced two new and linked concepts to the area of army management. Professionalism is an overall rating for a nation's land forces, while drill level is specific to each regiment. Well drilled units are more effective in combat, and having units conduct drill is one of the primary means of building up a high level of professionalism, which unlocks new abilities for a nation's armies.

Army professionalism

Each nation's army has a professionalism level (from 0% to 100%) measuring how closely an army models a professional standing army versus the feudal levies of the Middle Ages or the heavy reliance on mercenaries of the beginning of this period. The level of army professionalism can be found at the top of the military tab in the country view. It has the following effects, scaling from 0% to 100%:

	+10%	Land fire damage
	+10%	Shock damage
	+20%	Siege ability
	−50%	Regiment drill loss

These modifiers apply to all land units, regardless of whether they are normal troops or mercenaries.

Scaling down from 50% to 0% (max effect at 0%), there are also bonuses for recruiting mercenaries:

	−15%	Mercenary cost
	+15%	Mercenary manpower

Additionally, the value of army professionalism unlocks a new interface look and new abilities for armies every 20 points:

20% – Salaried Soldiers

May build supply depots: for 20 military power, an army can establish a supply depot in a friendly-controlled province. The supply depot will increase the friendly supply limit in the entire area by 50% and all friendly troops will reinforce as if they were in their home territory (ie the local reinforcement rate will be 100% instead of 50% even outside the national borders). If the province is occupied by a hostile force, the depot will be destroyed, otherwise it lasts for 5 years.

40% – Regiment Mustering

May refill garrison: allows a unit to take some of its infantry strength to restore the garrison of a fort instantly, working in your own forts, as well as friendly and occupied enemy forts.

60% – Conscription Army

Regain manpower when disbanding: instead of the manpower disappearing, disbanded regiments now return their soldiers to the manpower pool.

80% – Permanent Army

−50% Reduced morale damage taken by reserve – regiments not deployed during a battle normally still take morale damage, but will now take −50% as much.

100% – Professional Army

−50% General cost

+100% Army drill gain modifier

There are certain actions that will increase/decrease the army professionalism value.

• Drilling armies (+1% per year if 100% of the force limit is drilling, to scale)
• Recruiting generals (+1% per general)
• Recruiting mercenaries decreases professionalism by −5% per mercenary company
• Hitting the Slacken Recruitment Standards button (adjacent to the buttons for activating and deactivating forts) will lower the army professionalism by −1% (to a minimum of 0%), but will give a nation +200% manpower recovery speed, and −5% yearly army professionalism.

	Traditions	Ideas	Bonuses	Policies
+0.25%	—	Takeda idea 6: Twenty-Four Generals	—	Infrastructure-Quality: Handpicked Recruits Act
+0.20%	—	—	—	Court-Quality: Special Forces Act

Certain events and decisions will influence army professionalism as well.

List of countries in 1444 starting with army professionalism

10%

• Aztec
• Bohemia
• Burgundy
• Castile
• Geneva
• Livonian Order
• Mamluks
• Ottomans
• Switzerland
• Teutonic Order
• The Knights
• Three Leagues

5%

• Afghanistan
• Ajam
• Aragon
• Ardabil
• Fars
• Ferrara
• Florence
• Khorasan
• Lucca
• Milan
• Montferrat
• Mushasha
• Papal States
• Portugal
• Savoy
• Siena
• Timurids
• Transoxiana
• Urbino
• Venice

Drilling

A Muscovite army currently drilling.

Every regiment in a nation's army has an individual drill level (from 0% to 100%). Regiments with a high drill rating will be more effective in combat. Scaling with the level of a regiment's drill value the benefits are:

• +10% Shock damage
• +10% Land fire damage
• −25% Fire damage received
• −25% Shock damage received

Scaling up to 100, the average drill value of the regiments of an entire army gives:

• +20% Movement speed

Drilling can be initiated by pressing the drill button at the bottom of the army interface. Any non-mercenary army can be drilled as long as it has a leader assigned, and will automatically stop if the leader dies or is reassigned. Armies will also stop drilling when the country enters a war, but they can be drilled while at war. Mercenaries can only be drilled if it is explicitly enabled, for example via the mercenary idea 7 "Mercenary Recruitment". While drilling the army will incur the full maintenance cost regardless of the army maintenance slider on the budget screen, and its morale will be lowered severely. At the end of each month, the drill value of each regiment in the army will increase by a base of +0.83 per month, amplified by any drill gain modifiers.

During drilling, the leader of the army also has a chance of gaining additional leader pips. This likelihood depends on how much of the army they are drilling, relative to the force limit (around 10% yearly chance at 100% of the force limit currently drilling in a single army led by the leader).

A regiment's drill value will decrease for two reasons. When a unit takes losses (from battle or attrition) and receives reinforcements, the new troops are considered un-drilled and will lower the regiment's rating proportional to their numbers. (Example: an full strength regiment with 100% drill that takes 400 casualties will be at 60% drill when fully reinforced.) When not drilling, it degrades over time (base −0.083 per month), and both natural decay and decay from reinforcements are modified by regiment drill loss modifiers.

The speed at which armies are drilled can be improved with the following modifiers:

	Conditions
+40%	Enacting certain decisions (in exchange for increased maintenance)
+50%	Janissary units
+100%	from having maximum army professionalism
+50%	Sikh Guru
+25%	from Prussian missions
+25%	from Provencal missions
+10/+30/+50%	from holding Ambras Castle (only with Leviathan)

	Traditions	Ideas	Bonuses	Policies
+50%	—	Revolutionary French idea 6: Napoleonic Tactics	—	—
+33%	—	—	—	Infrastructure-Quality: Handpicked Recruits Act
+25%	Genevan traditions	PLC idea 3: Obrona Potoczna	—	—

The ammount of drill lost by decay and reinforcements is modified by:

	Conditions
−25%	Sikh Guru
−25%	Carolean units
up to −50%	scaling with army professionalism
−25%	The "Professional Soldiers" Janissaries estate privilege, for Janissary units
−25%	Rajput units|
−0%/−50%/-75%	Revolutionary Guard units, depending on associated decisions
−33% for 20 years	"Reform the military Manual" Government interaction of Prussian Monarchy
−33%	"Sustained Discipline" and "Compagnie d'ordonnance" Tier 5 Common Government Reforms
−33%	"Mansure Army" Tier 5 Common Government Reform
−25%	Dei Gratia Rex Golden bull for Catholic nations
−25%	Reform the Army Celestial Reform for the Emperor of China

Special cases

Amphibious landings

Amphibious landings from transport fleets will take 12 days to complete if moving into non-hostile territory, and 36 days if moving into hostile territory. Boarding a friendly transport from land will always take 12 days as well. These times are reduced by the maneuver rating of leaders. Marines disembark faster, as do units aboard fleets with the flagship modifications Integrated Marines or Portuguese Fusiliers. The modifier Hostile disembark time which is given to provinces by Coastal defence and Naval battery increases the time it takes for hostile armies to land.

Three way battles

If an army stops in a province in which two hostile forces are engaged in combat, it will wait on the sidelines and engage the victor once it emerges from battle. The victor from the first battle will now act as an attacker, and will suffer all terrain penalties appropriate for the province (unless that side controls a fort in the province, in which case it is the defender as normal). On the other hand, if only one of them is hostile, the newly arriving army will join the battle on the other side even if the non-enemy army is fighting in a different war.

Terra incognita

During peace time, only armies led by a conquistador may enter terra incognita provinces and explore them. In war time, all armies may enter terra incognita provinces if that province is controlled by hostile forces, but this is quite slow for a unit not led by a conquistador. If a terra incognita province is revealed while an army is attempting to move into it, its movement progress will immediately be updated, which can result in it teleporting into the province.

References

Mechanics

Defense

Fort • Zone of control

Customization

Nation designer • Random New World

Ages and Institutions

Ages • Institutions

Innovativeness and Technology

Innovativeness • Technology