I'd limit this to single civilizations: Christian to Christian, Moslem to Moslem. I don't think that a Moslem ruling class would have converted to Christianity, or that a Christian ruling class would have converted to Islam.
Alexandre [/B][/QUOTE]
Agreed, though this did happen in some occassions. e.g. the population of the whole of the Philipines was converted to Christianity when their King converted from Islam. Similarly, many Muslims states in SEA converted from Hiduism to Islam in the 1300-1400 when their Kings converted. And don't forget that many of the Coptic ruling class of Egypt, the south Yemen people and the Nubians were converted to Islam as well, almost en-masse, this happened before the year 1000 though, so no worries for the game.