There are basically two main types of mods: visual mods and data mods.

You can have as many visual mods selected as you want. These mods are managed from the Mods menu that you can access from the main menu. These mods do things such as changing graphics (e.g. terrain mods or small trees mods).

But you can have only 1 data mod active at a time. These mods do things such as changing unit stats (e.g. a balance patch that gives some units more attack). When you select one of these mods in a multiplayer game, then all players in the game must use the same mod (unlike visual mods), otherwise the game would go out of sync. Changing which civilizations are available is accomplished using a data mod, so if you have but the original AoC civs, then you are using a data mod that works only for those civs.

However, there are some graphical mods, such as giving each civilization its own architecture or unit graphics, that must be implemented as data mods in order to split the graphics files up for each civilization. These mods still are subject to the same data mod restriction: you can use only 1 at a time.

It is possible to combine data mods, but that must be done manually by creating a new mod using both of the mods files, and there isn't a simple in game tool to do it.

Thank you very much.

PLEASE delete this thread !