IDK who invented it. I will tell you the guy who invented "sauna yoga" won the World Yoga Championships like 4 years in a row (yeah, it's like the Olympics of yoga) before retiring because no one could beat him.
I refuse to take a class of "hot yoga" because I have done yoga outside in the summer in Tucson and I totally refuse to share that amount of sweat with that many other people in a very small room. It cannot possibly be sanatory.
I'm gonna guess an Indian God/Goddess invented yoga. Something. It definitely wasn't the Buddha due to fatness but like I can't even say that because my best ever yoga instructor was a retired NHL Ice Hockey player with a knee replacement by retirement and like, he was large. IDK about fat, but kind of brick shaped with skinny legs and stuff. You could hear his knee replacement click from time to time.
He got into yoga because he was miserable and sad and decided he wanted strength and flexibility back and he got into poses I have a snowball's chance in hell of ever getting into. He was pretty awesome and he was not all about "calmness."
His trick was, "Oh, let's try THIS impossible pose..... Oh, it's too easy for you guys!!!! Let's try adding THIS to it." Like five times in a row, kind of a last man standing thing.
It was sort of like the "Fear Factor" of yoga thing, only you PAID to be on the show and not the reverse.
Anna