Sounds like Mr Isaacson got up on the wrong side of the cage that day.*g* That being said, I think it depends on the intended audience, and who is choosing who the intended audience is. Last August I attended a series of workshops at a large Society for Creative Anachronism event. The workshops were on juggling, street performing, stage illusion-type magic, and such related things as they elated to medieval reenactment. They were taught by people who make their living this way (there's not a harder job on earth than being a professional fool), they treat their profession with respect, and they do their academic homework. When the authenticity question came up in the stage magic class, the teacher pointed out that, from what little documentation there is, the magicial chanted for perhaps up to half an hour, and then the illusion was performed. A modern audience would be bored, and losing the audience is not the point of performing. And even if they're dressed in the most authentic reenactment clothes in the world, they're still a modern audience. Then we went on to learn how to modify equipment so it wouldn't clash with the setting (eliminate plastic, etc). The point for musicians is, I guess, that the organizers of the event should decide just how authentic things *have* to be. The musicians should have done their acadmic homework regarding whether the piece is proper for the time period, since the onlookers might ask and learn something. If the intended audience is to be only academics, experts on the time period, than make the music as authentically academic as possible. If the audience is to be those folks who bought an admission to be entertained, then the parameters of repertoire and performance are different.