Quote Originally Posted by Grond
Offhand, does anyone know how high in valour the spies and assasins may rise?

I usually eschew border forts and use an assasin/spy combination instead (so they get credit for the kills). This gives me lots of 2-3 star intel people, some 4s, and every so often, a 5 (though many times the 5 seems to just be born that way- De Vere [Oxford!] from England is a 5 star at creation). While chopping up the HRE using assasins is great fun, especially after the 20th crusade has marched through Toulese again on their way to Egypt, I despair at getting better assasins/spies.

Also, I don't recall if there's a way to improve the stars on your religious folks, or an emissary.
It has been a little while since I've had a chance to play MTW, but I've seen 6 and 7 Valor assassins and spies. I did one further in my game, and edited watchtowers and border forts out of the game completely. This takes the game to a different level making assassins and spies even more useful. I still lose plenty of spies and assassins when I send them out on missions, as my opponents have spies and assassins of their own.

With the watchtowers and border forts gone, I've had reports of up to 10 assassins in a single turn being captured trying to get into Naples which had plenty of assassin bait (ie emissaries). Emissaries are great units to train up your spies and assassins.

The only place I've seen Valor 5 assassins get trained is from Syria. In Syria, assassins get an automatic +2 bonus, and then with the highest level tavern upgrade, they get an additional +3.

Watchtowers and completely give huge happiness bonuses (+50 happiness, which translates to loyalty), so removing them has the added effect of turning a province like Portugal or Scotland (for instance) even more difficult to keep loyal. I've seen a huge number of rebellions appear in AI provinces in games I've played with the edit. Usually when the Byzantines lose their naval ability you will almost often see frequent rebellions on their Mediterranean islands as they are cut off from their ruler.

As to Emissaries and religious characters gaining Valor, one way of improving Emissaries is to send them out to make alliances. Success gains them valor. Though I've not tested it, I believe that if you are successful in bribing a unit (drop your emissary on a stack) it can also gain Valor. I believe successful alliances also gain religious types Valor. I can't yet say much more about the priest characters valor enhancements because I find I rarely get any priest characters with more than 0 Valor.

I'm currently writing a more complete guide to the various agents, and I've gotten through Assassins, Spies, Emissaries, and Princesses. I have yet to get into the religious agents (bishops and inquisitors), but the thread in that link should have some useful information.