Hmm...now that I think about it that makes sense. There are even an ubiquitous amounts of examples to back your post up; from the Black Guard in Morocco to arguably the early Janissaries, though the latter became entrenched and "Praetorian" anyway.

And one of the ways European leaders liked to use the Swiss for. Was it the Pope who had a Swiss Guard or some such?

I agree they should be looked at from a different perspective than "normal" mercenaries. These units tend to have a certain absolute loyalty to their patron lacking in the usual mercenary business.

Though I'm still wondering what Machiavelli meant by that passage. Was he really distinguishing "national" armies -- including full-time salaried professionals -- and the condottieri, or was I reading too much into the passage? Machiavelli was a very innovative political thinker and I wouldn't put it pass him; then again The Prince is actually a work based very much on Renaissance thoughts of the time, especially on the Italy that Machiavelli knew, when and where "national" armies have yet to exist in concrete form...