Monasteries will remain dead forever, sadly...
Btw, you better make a new save if you didn't reach far in the game because all the christian towns and villages (90% of the map) will have -56 with you (that is, if you raided every single existing monastery)
And from personal experience, paying 500 for 3 relation points (you'll need 9500 exactly for positive relation) can hurt, esp if you're low on salary (that is on villages, and you WILL need them if you plan on conquering smth)