"The Marriage of Likeness: Same-Sex Union in Pre-Modern Europe."  It's tough going, but he makes an interesting case for similar arrangements being basic marriage contracts between people of the same sex.  I have to admit that I don't think that our concept of same-sex marriage is anything close to what either your scholar or Boswell cites in their books.  

I think however that it's wonderful that examples of early homosexual relationships are being shared in the MSM, which will hopefully get it into some morons' heads that gays go way back, not just to the '60s.