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Espionage idea group.png Espionage
Spy network construction.png Efficient Spies
+50% Spy network construction
−10% Advisor costs

Diplomat.png Agent Training

+1 Diplomat

Foreign spy detection.png Vetting

+33% Foreign spy detection

Aggressive expansion impact.png State Propaganda

−20% Aggressive expansion impact

May fabricate claims for subjects.png Claim Fabrication

May fabricate claims for subjects
−25% Cost to fabricate claims

Embargo efficiency.png Privateers

+25% Embargo efficiency
+33% Privateer efficiency

Yearly corruption.png Audit Checks

−0.10 Yearly corruption

Idea bonus.png Bonus:

+50% Rebel support efficiency

Associated events: Espionage idea group events

Espionage is a way to weaken enemies without actually going to war. In Europa Universalis 4 espionage works somewhat differently than EU3: there are no longer any spy agents, but covert actions are present. Rather than spies, diplomats perform espionage. Espionage has an associated idea group in the diplomatic group of ideas. This group unlocks several espionage actions, and makes espionage more powerful.

Spy efficiency

Spy network construction

Covert actions are executed by sending a Diplomat.png diplomat to construct a spy network in a foreign nation. As the spy networks' size grows more covert actions become available to the aggressor in the target nation. As long as the aggressor has a big enough spy network it is possible, if so desired, to perform a succession of covert actions on the target; All of which will be instantaneous and successful upon execution, along with most of the actions also having the effects lasting for a duration of Time Icon.png 5 years.

Spy Network Construction is modified by the following:

Spy network construction.png Triggers
+20% Trading in Spices.png Spices
-50% Corruption.png Corruption (at 100%)

Spy network construction.png Traditions Ideas Bonuses Policies
  • Espionage idea 1: Efficient Spies
  • Daimyo traditions
  • Ito traditions
  • Ardabili idea 5: Religious War
  • Aztec idea 7: Pochtecayotl
  • Hosokawa idea 6: Yamabushi
  • Kitabatake idea 6: Iga-Ryu
  • Kuban idea 4: Usurpation of the Chiefs
  • Lunda idea 7: Lord of the Vipers
  • Munster idea 7: Enemies Within
  • Pattani idea 3: Smuggling Networks
  • Samtskhe idea 2: Proactive Diplomacy
  • Tokugawa idea 2: Strengthen the Sekisho Network
  • Transoxianian idea 3: Adept Diplomacy
  • Trebizondian idea 7: Greek Scholars Abroad
  • Uesugi idea 5: Nokizaru
  • Frankfurter idea 4: Frankfurter Postzeitung
  • Italian idea 6: Italian Diplomacy
  • Sligonian idea 4: A Different Way
  • Takeda idea 3: Information Network
  • Ulster idea 6: The Defenders
  • Espionage-Offensive: The Black Chamber Act

Passive Benefits

Having a spy network in foreign nation grants several passive benefits for the aggressor in that nation. The benefits scale with the networks' size and at a 100 spy network will apply:

  • Siege ability.png+20% Siege ability
  • Aggressive expansion impact.png-10% Aggressive expansion impact (in that nation)
  • Technology.png-30% Technology costs, reduction depending on how far ahead they are than the aggressor - only highest reduction per tech applies (Note: Requires Espionage idea group.png idea 1: Vetting).

Discovery chance

Spy network construction has a Discovery chance upon reaching size 25; meaning, an aggressor can keep on fabricating claims or generating Trade conflict CB without risking the chance of being discovered as long the network size is smaller than 25.

The Discovery chance is calculated as the sum of the Yearly discovery chance, which has a base of 25%[1] (or a 2.083% Monthly discovery chance), and the difference between the defending province's Spy defense and the attacker's Spy network construction. While there are modifiers reducing the discovery chance, it cannot be reduced below about 0.06% per month.

A nation which has been discovered building a spy network will have it's diplomat sent back and restricted from further developing the spy network for Time Icon.png 5 years[2]. In addition, the size of the spy network will be reduced to the nearest 25 milestone. I.E., being discovered at spy network 70 will reduce the spy network to 50.

Foreign spy detection

All spy defence is ultimately provincial, the total spy defence being the sum of the national spy defense and the local spy defense of that province. All spy actions other than Fabricate Claim use the spy defense of the capital. Each base tax Development level in a province adds Local spy defence.png+1% Local spy defense so consider prioritizing the capital's tax development if neighbouring countries take Espionage ideas.

National spy defense is modified by the following:

  • +5% per point of stability
  • -10% to +10% from Prestige
  • +25% from trading in Tobacco
Foreign spy detection.png Traditions Ideas Bonuses Policies
  • Espionage idea 3: Vetting
  • Cascadian idea 4: Settling the Boundaries
  • Three Leagues idea 2: The League of God's House
  • Dahomey idea 4: Lagredis
  • Venetian idea 4: Found the State Inquisition
  • Chimu idea 4: Watchfulness of the Moon
  • Italian idea 3: Italian Aristocracy
  • Ormond idea 5: Irish Rivalries
  • Defensive-Administrative: The Spy Discovery Act
  • Espionage-Administrative: The Royal Commission Act
  • Espionage-Expansion: The Loyalty Act
  • Exploration-Defensive: The Naval Secrecy Act
  • Religious-Espionage: Enforce Religious Law
  • Creek traditions
  • Sligonian idea 4: A Different Way
  • Ulster idea 6: The Defenders
  • Takeda idea 3: Information Network

Local defense is modified by the following:

  • +1% per provincial base tax
  • -1% per local unrest

Covert actions

  • All actions are instantaneous and successful upon execution. Most actions have a duration of Time Icon.png 5 years.
  • Actions can still be executed even if a diplomat can't further build a spy network (due to discovery).
  • Same type (covert action) effects are not additive; I.E., Agitate for Liberty effects will apply only once per nation even if 2 or more aggressor nations executed it on the target.
Action Cost Requirements Effects DLC
Agitate for Liberty
Liberty desire.png+25 Liberty desire The Cossacks.png
Corrupt Officials 25 Espionage idea group.png idea 7: Espionage Yearly corruption +10 Corruption per year Mare Nostrum.png
Fabricate Claim 10 Have a neighboring province to fabricate a claim on Gain a claim on a target's neighboring province
Infiltrate Administration 40 Espionage idea group.png idea 7: Espionage Lift the Fog of War from the target nation
Justify Trade Conflict 10 Trade power.png Have at least 10% trade power in the same trade node as the target Gain a Trade Conflict CB against the target Wealth of Nations.png
Sabotage Recruitment 80 Espionage idea group.png idea 5: Shady Recruitment
  • Manpower recovery speed.png-20% Manpower recovery speed
  • Manpower recovery speed.png-20% Sailors recovery speed
Mare Nostrum.png
Sabotage Reputation 60 Espionage idea group.png idea 4: Rumormongering Diplomatic reputation.png-3 Diplomatic reputation
Slander Merchants 70 Espionage idea group.png idea 4: Rumormongering Trade power.png-33% Global trade power Mare Nostrum.png
Sow Discontent 80 Espionage idea group.png idea 6: Destabilizing Efforts
  • National unrest.png+3 Unrest
  • Depending on government type:
  • Legitimacy.png-1 Legitimacy
  • Republican tradition.png-0.5 Yearly republican tradition
  • Devotion.png-1 Yearly devotion
  • Horde unity-1 Yearly horde unity
Steal Maps 50
  • Espionage idea group.png Full idea group
  • Target discovered regions unknown to us adjacent to regions we know of
Steal target's maps of a region Mare Nostrum.png
Support Rebels 60 Any rebel faction has a greater than zero unrest Rebel support efficiency.png+10% Revolt progression chance for target's selected rebel faction

Fabricate claims

Using 20 points of spy network will fabricate a claim on a neighboring province, or a province that shares a sea zone with an owned province. Once a claim is established, the claimant now has a legal reason to start a war and gains the conquest casus belli. Claimed provinces allow a nation to select them as a wargoal when declaring war. Provinces with a claim cost less warscore in peace deals and have -10% coring cost, as well as only having 40% autonomy, instead of the usual 50% for unclaimed conquered provinces.

A fabricated claim lasts for 25 years, and will only be removed if its time runs out, if the province is cored by the claimant or if claims are simply give up in a peace deal. Claims cannot expire naturally if the claimant and the owner of the province are at war or have a truce, and their duration will automatically be extended to account for this. Despite the listed expiration dates on claims, the game only checks for their removal on the first day of each month. This gives the claimant a small window of opportunity to declare war again if the claim was extended by a truce: while truces are normally removed on the first day of each month as well, one can force them to expire on time by saving and reloading the game. See truce for more details.

Claims that are granted by missions behave just like fabricated claims, although their duration may be different depending on mission parameters.

Cannot fabricate a claim on a country while at war with them.

The base cost to fabricate a claim can be affected by:

Cost to fabricate claims.png Traditions Ideas Bonuses Policies
  • Munster traditions
  • Naxian traditions
  • Espionage idea 5: Claim Fabrication
  • Chiba idea 3: Coalition With Kamakura Kubo
  • Cypriot idea 1: King of Jerusalem
  • Imagawa idea 1: Claim to the Shogunate
  • Isshiki idea 4: Reclaim Old Territories
  • Lorraine idea 3: Lotharingia
  • Northumbrian idea 2: The Memory of Northumbrian Hegemony
  • Papal idea 4: Donation of Constantine
  • Polotskian idea 1: Legacy of the Werewolf Prince
  • Provençal idea 1: Memory of Angevin Claims
  • Yaroslavlyian idea 1: Between Hammer and Anvil
  • Nizhny Novgorod ambition
  • Thomondian ambition
  • Brandenburg traditions
  • Saxe-Lauenburg idea 1: The Partition of Saxony

Decisions and events:

Cost to fabricate claims.png Event modifier Trigger Duration
−25% Aphra Behn Flag of England Flag of Great Britain Women in History event: “Aphra Behn
Option: ‘Keep this a close secret!’
for 20 years.
Emperor condemns Tuscany Flag of Tuscany Tuscan event: “The Emperor Condemns Tuscany's Elevation
Option: ‘The Emperor will not stand in the way of God's will.’
for 20 years.
+50% Limited Claim Fabrication Diplomatic ideas event: “Incompetent Diplomats
Option: ‘They are of noble blood though...’
for 5 years.

Claiming colonies

'Inter Caetera' the third national idea of Spain/Castile allows the use of fabricate claim on colonies which normally wouldn't be in reach of that action. This allows Spain/Castile to target colonies both inland and distant overseas, making any colony in the world a potential target. (This special ability can no longer be used once the colony turns into a city at a population of 1000.)

Support rebels

Main article: Rebellion#Support rebels

This will increase the unrest of that rebel faction in the target country. The player may choose to support any rebel faction that has a greater than zero National unrest.png unrest anywhere within the target nation.

Supported rebels will be treated as allied units, regardless of when the support them began. If the rebel faction has spawned rebel units in multiple countries, then all those units will be treated as allies once support is given to that faction anywhere.

Allied rebels that are sieging a province that is an objective of theirs will not transfer leadership of the siege to the player in a war. If allied rebels cannot complete their objectives because the province they are trying to occupy is under another nation's control, they will instead wander the countryside and may engage enemy units.

Rebel support efficiency.png Traditions Ideas Bonuses Policies
  • Full Espionage
  • Espionage-Economic: The Foreign Support Act
  • Samtskhe traditions
  • Piratical idea 7: Life of Liberty
  • Humanist-Espionage: Cultural Understanding
  • Leinster idea 3: The Subject of My Enemy is My Friend
  • Palatinate idea 3: Center of Reformation in Southern Germany


Networking icon
Have 100 point spy networks in 3 rival nations.
Just Resting In My Account icon
Just Resting In My Account
Corrupt the officials in a rival country.
Time Bandit icon
Time Bandit
Successfully steal a map from another nation.


  1. See in /Europa Universalis IV/common/defines.lua: BASE_SPY_DISCOVERY_CHANCE = 0.25,
  2. See in /Europa Universalis IV/common/defines.lua: SPY_DISCOVERY_COOLDOWN_MONTHS = 60,