Portland Revels has done two shows of a Celtic nature. The first, in 1998, was broader in focus, encompassing traditions from Scotland, England, and Wales. (Don't quote me there--it's been nearly twenty years, and I'm going by memory.) These are very large images; click on them to see what isn't fitting on the page.
After that came the first French Medieval show, in 1999.
Then, in 2000, a Victorian Show.