In the Sims 2, I had custom careers, skins, and a very active imagination. One of my towns was a neo-medieval (well, a weird medieval-western fusion) city in which monks and nuns were important (serving as teachers and doctors, respectively), and there was an order of knights who dominated the military and politics. One of my uni houses was a clerical greek house designed like a monastery, with a rectory, a chapel, and sleeping areas. At first this religion was just inspired by medieval Christianity, but I later made it overt. The neighborhood also had a Muslim community, inspired by Iranian and Shiia customs which I'd been reading about at the time. I never extended this religious approach into TS3/TS4, in part because we don't have the creative control over our neighborhoods the way we did in TS2. In TS2 I literally created the map from scratch.
http://3.bp.blogspot.com/-PBjLqGIWpZM/Uc-bTFOK_sI/AAAAAAAAAgY/4oSf6QYQhfc/s1600/Harriet-matthias.jpg
I don't have any shots of the religious elements available, but the above might give some idea of the historical 'feel' of the neighborhood.
