To better reflect the character of the 12th-15th centuries, Age of Chivalry: Hegemony replaces or significantly alters each of the civilizations in the original game, adding many new units and technologies, allowing the player to control Central and Western European states.
Can't say how the mod affects multiplayer but for singleplayer this is a blast. A huge amount of new assets to play with which most importantly look good so they fit into the game and stat wise are also making sense. Many new civilizations with their own unique look and buildings and units make this for me a true AoE3.
A lot of effort has gone into this mod, an effort I greatly appreciate as its outcome is fantastic. Many thanks.