The Tales Of Robin Hood & Other Folklore

Back in the olden days people in England (and other parts of the northern hemisphere such as in Sweden and other Norse countries) celebrated the
end of winter by throwing a big party on the first of May.

Festivities included May-pole dances, May kings and queens, and the following two characters who played a major role:

Maid Marian and Jack in the Green.

Jack in the Green was usually portrayed...all in green! Did you expect anything else?

Anyway, he was covered from head to toe in green ivy and garlands of flowers, to signify the rebirth of spring and fertility.

As for Maid Marian, she was a simple shepherdess whose role may have derived from a 13th century French tradition of having May Games that involved the love play between the Maid Marian (or Marion in French) and her lover Robin just as the rest of nature gets ready to partake in similarly lewd activities.

Le jeu de Robin et Marion

Over time, the myths may have merged to create a more humble Maid Marian and her lover Robin in
the Green, who still frolicked in the forest (which could have been Sherwood Forrest, who knows?).

A few centuries later, Robin and Marian were both gentrified then even later associated with actual personages during the reign of King John, brother of King Richard... and of course, over time, many others have tweaked the tale to fit their needs.


Sources:
Myths of the Norsemen: From the Eddas and Sagas (Barnes & Noble Library of Essential Reading)
Wiki - Jack in the Green (Note: I swear I came up with this comparison before reading this article!)
Wiki - Maid Marian