Fort

Forts are super-strong defensive structures, and are also used to train a variety of units. Officers, spies, and all gunpowder infantry and siege units are trained from your forts.

Forts are available once Level 3 Military (Heraldry and code of honour) is researched, and depending on what you have researched, you can upgrade your forts to castles, and towers to keeps and bastions. Forts and Towers are upgraded to Castles and Keeps once Fortifications is researched, and can be upgraded again by Asian and Orthodox factions with Imperial Mandate at the Nobles' Court into Strongholds and Keeps, which are immensely strong.

Note, however, that despite being strong, Forts are vulnerable to siege weapons. The trebuchet, having the furthest reach in the entire game, can easily wreck anything with impunity regardless. Of lesser damage caused would be naval units, namely the Siege Galley; Carrack and Lanternas; a Castle with Military Engineering can match a Siege Galley in range; with Bombardment, Carracks are caught. Only a Stronghold with Bombardment can hope to hold off an attack by the Lanternas, and even so, several Lanternas will easily destroy a Stronghold through sheer determination and numbers.

Units trained

• Officer
• Spy
• Arquebusier
• Culverin
• Bombard

Upgrades

Fortification 

Without Fortification, Castles will well fall foul of enemy siege units. Fortification enhance a fort's tactical capabilities as well as its effects on your borders.

Fortifications

Good walls make the best neighbours.

• Increases border push effect of all forts and castles.
• Increases offensive power and range of all forts and castles.
• Required for Castle

Cost	Requirements	Leads to
150; 150 Time to complete: Fast	[2]

Military engineering

A pile of stones can either be a mighty wall or a fearsome weapon — only as long as one knows how to use them as such.

• Increases border push effect of all forts and castles.
• Increases offensive power and range of all forts and castles.

Cost	Requirements	Leads to
300; 300 Time to complete: Rather fast

Bombardment

"Point this end away from self towards enemy."

• Required for all gunpowder units, with exception of Chinese Fire Lance Infantry and Divine Ordnance Division
• Increases border push effect of all forts and castles.
• Increases offensive power and range of all forts and castles.

Cost	Requirements	Leads to
450; 450 Time to complete: Medium

Strategy

Strategy upgrades enhance the reliability of spies, and are also required for the creation of generals.

Order of Battle

Any fool may know to fight, but a fool who picks the right battles and the right weapons is no fool, but is instead a general.

• Production speed increased for Officers, Spies, Fedayeen, and Hashishin
• Increased armour for Officers

Cost	Requirements	Leads to
80; 80 Time to complete: Fast

Strategy

"Any man may see the tactics which allows me to win battles, but not the strategy which brings me victory." —Sun Zi

• Craft recovery rates increased for Officers, Spies, Fedayeen, and Hashishin
• Increased armour for Officers

Cost	Requirements	Leads to
150; 150 Time to complete: Rather fast

Operations

Preparednes for war is sometimes far more important than winning a war itself.

• Increased production speed on Officers, Spies, Fedayeen, and Hashishin
• Increased armour for Officers
• Required for Fire Vessel

Cost	Requirements	Leads to
300; 300 Time to complete: Rather fast