May Day may have been an idea common to the Celts and the Germanics. It was Beltane to the Celts; I don’t think I know a name for a pagan Germanic day, other than just May Day. This day marked when the cattle could go out to pasture again, with the snow and mud gone, and some new grass. But it was a festival about the wild woods, not the cattle.
We can only speculate how it might have been during pagan times. Tacitus tells us that the Germanic tribes the Romans met had an idol that went about in a cattle-drawn wagon, from town to town, until it was immersed in a hidden secret lake. Could a ritual like this have inspired a festival for going deeper into the uncleared forest? The drama for May Day is about wild men living in the forest: what was that about originally?
In medieval times, England’s May Day was primarily a holiday for young people to gather wildflowers and walk in the forest. Girls in flower garlands and a May Pole on the green for dancing, what’s not to like? But this bowdlerized version covers the darker side of May Day: slipping off into the woods for illicit sex, just in time to conceive a crop of Christmas babies. August’s a great month for a shotgun wedding, don’t you think?
But by the High Middle Ages, May Day was also about amateur folk plays about wild men in the woods: specifically, Robin Hood. Now, Robin Hood seems to have been more like Batman than like Billy the Kid (in that Billy was real). His name emerged from a group of folk ballads about outlaws from the Norman “forest laws.” His character changed through the ages, adding complications as each age spruced him up for their values. May Day dramas about Robin wanted flowers and girls, to go with May Day, so “Marion” or “Marian” joined Little John and Friar Tuck in his cast.
Marian seems to be a blending of an older Celtic “May Queen” festival and the contemporary emphasis on the Virgin Mary, for whom she was named. She was a shepherdess in some versions, but as time went on, her status rose—as did Robin’s, until he was a nobleman in disguise, not just a yeoman with his longbow.
May Day plays were probably a combination of local productions and shows put on by traveling players. We have an early Robin and Marian play written in French from about 1282, though scholars are not sure it’s the same Robin and Marian. It emerged from the town of Arras, in France, where there was an especially strong theater tradition.