Of course there was anesthesia before ether. The difference was that they used drugs and sedatives, mostly opium, henbane, nightshade, and the like. Or whisky, another popular choice. Not super-safe for waking up again, but you’d be asleep and feeling no pain.
Of course, today most operations are carried out with anesthetic drugs, not anesthetic gases. Because the drugs are now safer.
Dwale: an Anaesthetic from Medieval England. Ingredients: bile, hemlock, bryony, lettuce, opium, henbane, vinegar, and a half-gallon of wine. Talks a fair amount about medieval use of “sleeping medicines” and “drowsy syrups,” and why there was trouble getting the dosage right.
Aliens in This World 
Oh, thanks! I love bits of medieval tech and science.
BTW, I ran across a mention of dwale a few years ago. I don’t recall if that author went into a lot of detail, but that particular writer speculated that the bryony might actually be part of allowing people to survive the drink, because it was a purgative. As in, hopefully after you were done operating, you could get the patient to toss all the rest of the drug before it could be further absorbed.