I assume that you mean Thomas Burnett Swann. I read several of his books, which were then readily available in paperback, back in the early and mid-seventies. I don't remember any of his books being sword & sorcery, though. Maybe some of them were, but most of them were ... fantasy based on mythology, yes, but pastoral and romantic (mildly erotic) in their themes. His writing, as I remember it tended to be lyrical and poetic—not surprising because he was also a poet.
Thomas Burnett Swann . Typo on my part and the spell checker corrector . My bad on that and , I made assumptions.