Cause they're just one faction. If we really did go with another dating system, it'd be one that was common over more of the map at our starting time roughly. That wouldn't be A.U.C. for sure. It probably would be Olympiad dating or something like that, but that really wouldn't do either, so we just use dating most players will understand. We've had serious discussions over this and realized it's just not possible to change this part of the game engine (if you could alter dating based upon faction or culture, now *that* would be awesome).