There is a thread with the ruling in the New Card ideas section regarding Foreign Wives and Fortify site, and I wanted to post it here as the situation may come up often.
Fortify Site
Search discard pile for a black Canaanite or a Canaanite Site and put it in play to discard an artifact. Protect it from opponents while it remains in territory.
As a clarification, cards that use "while it remains in [a location]" are active until the point in which they are removed from that location. So Judas may be discarded or converted after being set-aside until his ability reactivates (which has long been the ruling) and Foreign Wives (or any other Canaanite) is only protected until the point when it leaves territory. If it returns to territory, the protection is no longer active.
