Originally posted by zebanoI think you have it backwards-- stalemate was a win for the person forcing the stalemate.
Actually I think it's more that in that era a stalemate was a loss for the person forcing the stalemate. Hence Nb7+, Qxb7 and white wins.
Edit: this page has a summary of old chess rules: http://chess.eusa.ed.ac.uk/Chess/Trivia/OldRules.html (can't vouch for its accuracy).