Science - Fiction book title or author?

[lark]

I'm trying to remember a book or series where humans were captured from a ship at sea and ended up as warriors. The ship might have been medieval. They were shuttled from planet to planet to fight, possibly in stasis. The nobleman of the ship was the leader of the group and was called to an alien's office about assignments or battles. The nobleman's wife might have been also captured. They eventually planned a rebellion and captured a ship or ships. I think that they had reached the present day by time of the rebellion. There was also mention of some type of a federation of worlds with which the alien captors were associated. I seem to remember some type of Roman imagery, though I can't remember if it was that Romans had previously been captured, clothing, or battle tactics.