Fortress

"Fortress" is the generic name given to massive fortifications which can garrison troops as well as increase your borders. Aside from this, they are also the pickup point for key units, most notably Generals and select elite units. The most notable military unit to be trained here are the War Elephant lines, trained by the South Asian factions — India, Vietnam, Siam, Burma and the Malays.
Unlike other mods and Rise of Nations itself, the many defensive structures that make up the Fortress line do not upgrade to each other. Instead, they are one and separate, and in order to reach the next one you must research the maximum level of Fortification available to obtain the next Fortress-type building.
==Structures==
*Stocakde and Martello Tower - a cheap but powerful cannon-based defence that can be garrisoned but must be built within your borders, armed with light cannon. Last upgrade requires Trace Italienne.
*Blockhouse and Bastion, like the house, but can't be garrisoned, these buildings function primarily as light point defences that can be constructed outside your territory. This pairing requires the Attrition line.
Name 	
Abilities	
Resourcecost	
Requirements	
Special remarks
Castle 	
*Does not attack, but has substantial LOS
*Can detect hidden units.	
*Base:: 120;: 120
*Ramp:: 25	None	
Fortress	
*Substantially stronger than House, but can't be garrisoned.	
*Base:: 120;: 30
*Ramp:: 10	
:  	
*Attack: 10, Armour 4
*1,500HP
*+1 Min range
*Upgrades to Bastion
Citadel 	
*Upgrade of Blockhouse	
*Base:: 150;: 50
*Ramp:: 30	
* 
* 	
*Attack: 12, Armour 5
*1,750HP
*+2 Min range
<tabview>
Fortress/Rise of the Moderns|Rise of the Moderns
Fortress/Ultima Ratio|Ultima Ratio
Fortress/The Age of Conquest
</tabview>
Category:Defensive structures