Jerrith said:In that case, I believe it spread because the overall ruler (you) is still considered to be doing the converting, it's in 'your' realm even though its your vassal - you were doing the converting. I'm assuming your liege has greek culture?
I missunderstood your question. Assmilation is to the culture of the king or top liege in the kingdom. If none of the provinces has his culture, then there will be no culture spread.
Alexandre