The Fortress Age is the third Age in Age of Empires III. It is characterized by the beginning of fortification in the civilization's colony, the mobilization of heavy artillery, and the improvements of the economy. More advanced cavalry and infantry units become available in the Fortress Age including the Falconet.
The Feudal Age if followed by the Industrial Age.
Available politicians
Advancement to the next Age requires the selection of a politician to advance with. Different civilizations have different politicians available depending on Home City level and civilization:
| Politician | Bonuses |
|---|---|
 |
Ships 1 Caravel (1 Galley for the Ottomans) and 400 wood |
 |
Ships 7 Longbowmen (British)/17 Streltsy (Russians)/4 Pikemen and 4 Crossbowman (Spanish) |
 |
Ages up 2.75 times as fast |
 |
Ships 1 Privateer and 2 Barbary Corsairs |
 |
Ships 6 Skirmishers (4 Abus Guns for the Ottomans, 6 Cassadores for the Portuguese) |
 |
Ships 3 Iroquois Mantlets and 2 Native Scouts |
 |
Ships 4 Hussars (5 Cossacks for the Russians) |
 |
Ships 5 Halberdiers (Dutch)/3 Doppelsoldner (Germans)/8 Pikemen (Spanish) |
Available units and buildings
- Artillery Foundry
- Arsenal (can be accessed in the Colonial Age after shipping the relevant Home City Card)
- Dojo (Japanese)
- Fort - All infantry, cavalry, and artillery, except artillery pieces (Mortar, Falconet, Culverin, and Heavy Cannon) are available.
- Nobles' Hut (Aztecs)
- Plantation (can be accessed in the Discovery Age after shipping the relevant card)
- Siege Workshop (Iroquois)
Template:Ages (Age of Empires III)