I seem to recall the Kerr clan of Scotland being noted for producing left-handed warriors. FWIW, there are also a few biblical reference to left-handed warriors, namely Ehud who ruled Israel for a time, and an elite group of left-handed Benjamite warriors.

Being a left-handed swordsman myself, I don't really notice that much difference between fighting lefties and righties. The key is focusing on the openings as they show up, not whether the opponent is cross-handed to you. There are a couple of images in Talhoffer... one showing someone who shifted his sword to his left hand to strike around a duelling shield, and the other is someone with a dagger concealed behind his back, with the caption stating that he could strike with either hand. I don't think that the practically-minded swordsman of the middle ages and renaissance would care what handedness one was, as long as one could fight well. As an aside, considering the potential of injuring a dominant hand in combat, how many would have been forced to use the left hand anyway?

Sinistrally,

-Mark :)

I am left handed
that being said,I have never recieved any sword training but when I was in martial arts.

I was taught to fight right and left handed as my teacher said it would be a great advantage because of the different "looks" at your oppenent from him facing essentially the "wrong" way