Wiki entry for maypole dance. Looks like the ribbon-dance may be a much later add. I think I'd like to take a walk-through of the UMD liberal arts journals database, just to see... There are several websites with all sorts of information on May Day rituals and absolutely no citations at all. I've seen references to Hermia calling Helena a "painted maypole" in "Midsummer's," and a Puritan ban on them in 1644, so I'm willing to believe their antiquity, but I don't know what details we may or may not have.