Googling "Byzantine era anesthetics" brings up a whole long list of research papers and articles. Apparently (from the summary of one of the articles) opium ha

Googling "Byzantine era anesthetics" brings up a whole long list of research papers and articles. Apparently (from the summary of one of the articles) opium has been used as a pain killer for a very long time, and the Byzantines used laudanum. https://rhm.sums.ac.ir/article_45640.html https://rhm.sums.ac.ir/article_45640.html Maybe they knocked the guy out with laudanum before the procedure, which would have made the whole thing much easier and far less unpleasant for the patient.