Age of Emperors, written by Shay Roberts,  is a dramatic expansion of the Rise of Rome scenario included in the Conquests.  Many new units and improvements have been added.  It can be played solo or multiplayer.

Here's a sampling of the innovative game features...

• Unlike normal Conquest games, the AI will build armies and use them in battle against you! Prepare for a whole new way of creating armies.
   

Roman Army

Persian Army

Macedonian Army

Carthaginian Army

• Relaxed shallow water rules: large ships can enter any coastal city but are slowed when traveling through shallow water. Small ships travel more quickly through shallow water but are more vulnerable on the high seas.

• Cultural warfare: unique improvements that generate only culture points allow small civs to compete culturally with large ones.

• Wide variety: This large mod pack contains three full scenarios that present very different playing environments. Play on land or at sea. Play solo, multiplayer, or as a team. Play historical or fictional scenarios. Play on pre-made or freshly generated maps. You choose. There is something here for everyone!