Could you please check my English translation from the Medieval Latin below?

Phos, I'm pretty much with Caudex. I would, however, come down on the side of translating "dux" as "leader," rather than as "Duke," since the intent of the sentence seems to be be to convey the idea that Arthur, rather than the kings of the Bretons, was the overall *leader* in the battles/wars. I think using "leader" in this passage more clearly conveys the idea that, while Arthur fought alongside those Breton kings, Arthur nonetheless remained the leader. Just a small difference in emphasis, I suppose.