Idioms: "Bated Breath" or "Baited Breath"?

While working on a page for another blog, I found myself using the expression "bated breath." This one always bugs me because I know I'm spelling it right, but I always have to look it up because I just don't trust that darn word "bated." Where did it come from? Can I bate someone or something? If not, could I have a hundred years ago? Was it short for something? I can only think of a few words that end in "bate," and very few seemed logical or even appropriate.