I've used flax linen in the past, and some pretty nice wool, but from now on I'll probably be sticking to wool for the most part, as it's likely wool was more common than flax (Although it's probably linen was used to some degree). Unfortunately, the wool closest to what was used in ancient times is expensive pashmina fabric, quite hard to get as well. I wish I had access to local wool, but I'm going to have to settle for ordered higher end stuff right now.