Actually, I know of no official law forbidding it. However, as my character has never actually heard of any such objection from anyone, I can't do that, even if my character wouldn't consider the issue completely ridiculous. After all, any noble who can think without smoke coming out of his ears would realize that the idea of a foreign religion being active inside a *theocracy* is simply ridiculous, as well as it being no one else's damned business how Sorraine conducts their internal affairs. At least that's what Taylin would say, if she were writing forum posts. Except she wouldn't be so nice about it.
