…a strange madness came upon him. He crept away and fled to the woods, unwilling that any should see his going. Into the forest he went, glad to lie hidden beneath the ash trees. He watched the wild creatures grazing on the pasture of the glades. Sometimes he would follow them, sometimes pass them in his course. He made use of the roots of plants and of grasses, of fruit from trees and of the blackberries in the thicket. He became a Man of the Woods, as if dedicated to the woods. So for a whole summer he stayed hidden in the woods, discovered by none, forgetful of himself and of his own, lurking like a wild thing. –Geoffrey of Monmouth, 1150 AD
Source: Wild man – Wikipedia