You can deal with them in a number of ways, from walls with ballistae armed towers to local cohorts of troops. One of my postings was to the alps, just in time to meet Hannible and his elephant friends. My current assignment is to found Damascus, and I've been contending with cammel mounted archers. More annoying than really threatening. All in all it's a hoot of a game.
History does get bent in the interests of playability though.
But the graphics are very nice, the townsfolk are always willing to tell you what they don't like about the place, and it's sucked up lots of my spare time lately. This is an informal research convention concentrating on early mythology and religion, especially Mithraism and other cults of the Roman Empire. It is held in New Haven, CT, the home of Yale University. We plan to spend most of Saturday in Yale's Sterling Memorial Library doing whatever research your heart desires. The hotel is within walking distance of the library and gallery.