Well, there are two different types of fealty. There is the Tolkien oath - that's the one I swore before Roric crowned me Princess, and the one you swear sort of at the initial outset of your office so to speak. This one seems to be used when we are stepping up originally to whatever higher calling we are suckered into...er... taking on. ;) I swore that oath to Sig and Kamille, the then Prince and Princess.

The 'mindful that the harmony of your Principality/Kingdom' bit comes when you're offering your fealty to the Crown, specifically - that was the oath I swore every time the crowns changed hands as Bard of the West, and also as Princess when we swore to the King and Queen (and now as a peer).