There is a new book out: Robin Hood: A Mythic Biography, by Stephen Knight from Cornell University Press. Kinght is a professor of English at Cardiff University. He states that Robin Hood is a mythic figure who stands for resistance to corrupt authority, who continues to change his form, and operates as a kind of safety valve which is "the reflex of genuine political resistance to oppression." Here is an extensive review in Salon.com
" by 1600 there were at least 200 known references to Robin Hood, almost all stressing Robin's boldness and resistance to authority but as yet lacking a Maid Marian or a Friar Tuck (though Little John is around, not always as a sidekick but sometimes as an equal). Once the basics of the story were established, Robin began to acquire new companions, got himself involved in contemporary controversies, and became a wonderfully serviceable symbol for whatever social or intellectual currents happened to be sweeping through England in a given century."