yep: regarding the Swiss Guard & the Vatican:

"Swiss Guards are Swiss mercenary soldiers who have served as bodyguards, ceremonial guards, and palace guards at foreign European courts from the late 15th century until the present day (in the form of the Papal Swiss Guard)."

http://en.wikipedia.org/wiki/Swiss_guard

I haven't played the XL mod (haven't downloaded it yet)

but the Swiss mercenaries were my amongst my favourite units in MTW