Am I missing something?

[econ21]

Detailed instructions for unlocking the factions are given at the beginning of frogbeastegg's guide, which is highly recommended for new RTW players:

https://forums.totalwar.org/vb/showthread.php?t=38382

[Ciaran]

If you want to play the unplayable factions in 1.5, this is your link:
http://www.twcenter.net/forums/showt...834#post994834

Heed Quillians advice about the Senate though, it was never meant to be playable and trying to do so will cause all kinds of trouble (quoting Jerome Gadsky, one of the CA guys who, despite all, post occasionally in this forum)

[Avicenna]

Don't try the rebels, either.