- +2% Missionary strength
- −25% Missionary maintenance cost
- +1 Yearly legitimacy
- +1 Yearly prestige
- +2 Yearly papal influence
- +5% Discipline
- +1 Missionary
- +1 Land leader shock
- +25% Fort defense
- +2 Diplomatic reputation
- +25% National manpower modifier
The Kingdom of Jerusalem from the Crusaders era can be formed as Provence, Cyprus, The Knights, Athens, Naxos, Epirus and any other Catholic who moves his capital to the Arabia or Egypt region. It can also be released by any Catholic who can't form it. The kingdom itself existed for nearly 200 years and was the major Crusader State of that period.
You can't form Jerusalem after the Age of Reformation has ended.
Reestablish The Kingdom of Jerusalem
Jerusalem does not exist.
If the country is AI-controlled then it:
The country gains 25 prestige.
The AI will never enact this decision.
- Main article: Crusader missions
Cyprus starts in the best geographic position to form Jerusalem, as it can immediately fabricate claims on two of the three needed provinces. Or, building to max naval force limit, will unlock a mission that gives permanent claims on the required provinces. However, in order to invade the Levant, it is best to first build a power base elsewhere before invading lands that are difficult to convert (even with the added missionary strength), and also to secure strong allies against the Turks.
The quickest way to form Jerusalem for the achievement is to wait until the Ottomans inevitably attack the Mamluks, and then declare war on the Mamluks at the right moment, when the Mamlukean army is weak and the player can secure at least one fort near the province of Jerusalem. Take note that the player will be the siege leader as long as they place at least one unit on a fort province - so they can let the Ottomans siege down the province for them, and protect their army at the same time.
A more sustainable way is to follow the Strategy for Cyprus and expand to a solid power base in the Balkans and Anatolia (Ramazan is an ideal target if they have no allies), as well as convert Cyprus's lands to catholic, before invading the Levant. At the point the power base in Greece and Anatolia is secured, the player should be strong enough to take on the Mamluks on their own.
Another valid strategy is to build up relations with Ottomans and Mamluks waiting for the event that make Cyprus vassal of the Mamluks. This event will fire once your starting ruler dies, and your female heir replaces him. After the five years truce the player can call Ottomans and maybe others Mamluk's rivals in an independence war and take the required provinces.
As the Knights
In order for The Knights to form Jerusalem quickly, they will need to go via a claim on Cyprus, which is guaranteed by the Mamluks in the beginning, and may end up as their vassal after some time. Since The Knights start up being guaranteed by Venice, they can likely form an alliance with them quickly, and then - after building up enough favors - call them into a war against Cyprus, ideally when the Mamluks are being attacked by the Ottomans. It is important to note that Venice has a mission to conquer Cyprus, which gives them a claim on the island, and might make them hostile towards the player if conquered, however, joining their trade league may prevent this (requires Mare Nostrum DLC).
In order to take Cyprus - or the holy land itself - quickly, it is best for the player to wait until the Ottomans inevitably declare war on the Mamluks. The player can then declare war on Cyprus, and there are two possible strategies. In a two-step strategy, the player should attack Cyprus on their own as soon as the Mamluks are unwilling to join the war. (It is important that Venice does not have the mission to conquer Cyprus at this point!) If the player has taken care of building a stronger army and navy than their target, the player should have no problem taking the island, which can then be used as a base to forge claims on two of the three needed provinces (the Ottomans are unlikely to take those provinces during their first war with the Mamluks). The player can then wait until the Ottomans declare their second war on the Mamluks - or possibly even declare it on their own, with Venice's help - and take the necessary provinces.
The player may also attempt a one-step strategy, if they can see that the Mamluks are still willing to join a defensive call to arms by Cyprus (this will especially be the case if the Mamluks managed to vassalize them), and as long as Venice - and potentially other allies - are willing to join. Take note that if the Ottomans rival the Mamluks, they will likely grant military access to the player and/or their allies. The player should, in such case, wait until the Mamlukean navy and army are weak enough to make such an attack possible - most likely due to an ongoing war against the Ottomans - and make sure to beat the Ottomans to a fort around Jerusalem, as well as the necessary provinces, without getting their armies destroyed by the remaining Mamlukean forces.
The quickest way to Jerusalem is to secure alliances. Make alliance with Papal States' rivals to acquire your core province Avignon. Break those alliances. Use alliance with France to annihilate Burgundy. Improve relations with the Holy Roman Emperor to gain the protection of the Empire. Ally Castile and other Aragon's rivals to gain Barcelona, Valencia and Palermo. You should consider attacking allies of Venice in order to gain Crete. Chose right time to strike Mamluks. When they are in war with Ottomans, you will be able to defeat them.
With the Emperor expansion, Athens may form into Jerusalem.
Being an one province minor and vassal to Byzantium, Athens starts in a tricky situation. Restart the game until Byzantium rivals Venice then get Venice to support your Independence War. After which, improve relations with the Ottomans and hire the diplomatic reputations advisor if he's there, if not, restart the game or hope for an event that'll increase your relations with the Ottomans greatly. There's a chance that the Ottomans may have too many diplomatic relations by the time you're able to get them to support your independence, in that case, restart the game or rollback to a previous save. Once you've gotten the Ottomans to support your Independence War, declare independence on Byzantium, make sure to get your troops in Southern Greece first before Venice or Ottomans do, or you won't be able to take them in the peace deal. Once Byzantium loses take every province with the exception of Constantinople, as this will greatly anger the Ottomans, instead give them Constantinople if you can if they haven't already sieged it down for themselves.
After winning Independence, you can decide to dissolve your alliance with Venice if need be. Join any of the Ottomans wars and participate, as this will give you loads of favors, which may be useful in the future. Buy enough ships, transports recommended, to fill your naval force limit and hire an admiral. This will allow you to make use of the Crusader mission "Crusader Fleet" to get a free and permanent claim on the Palestine area. Afterwards, declare war on the Mamluks with your allies. The battle may be tough, but you should win. In the peace deal, take the three provinces required to form Jerusalem and if the Ottomans are particulary upset at the provinces (or lack thereof) that they got for their war participation, use the favors you accrued to increase their trust so that they won't break their alliance with you. After which, you should be able to form Jerusalem.
Formation decision and beyond
As soon as the player owns the three required provinces as cores, they may take the decision to form Jerusalem. The player should take note that this can change their national traditions and ideas if the player chooses to change them during the event following the decision, which may impact them negatively or positively.
After forming the Kingdom of Jerusalem, it is up to the player to decide whether they wish to expand into Europe, Asia or Africa.