Sega and The Creative Assembly has released details of another Tribe set to feature in their anticipated strategy title, Total War: Rome II. The latest group to join the line-up is Parthia, skilled horsemen and formidable opponents. Famed for their horseback archers and their bronze-clad heavy cavalry.
Historically their culture is a blend of Persian and Hellenistic cultures, they revered gods from opposing cultures and practiced Zoroastrianism (go on - look it up). An Eastern faction founded on trade, the culture was noted for their tolerance for others (though presumably that wasn't much consolation when they were invading you). More details are available on the Total War Wiki.