What is the origin of mondegreen?

The trouble with mondegreens is that they are usually so hysterically funny that you cannot stop citing examples of them instead of describing their “taxonomy” and history. Mondegreen was coined by the U.S. writer and humorist Sylvia Wright (1917-81), who wrote in an article in Harper’s Magazine: “When I was a child, my mother used to read aloud to me from Percy’s Reliques, and one of my favorite poems began, as I remember: ‘Ye Highlands and ye Lowlands, / Oh, where hae ye been? / They hae slain the Earl Amurray, / And Lady Mondegreen,’” the last line being a child’s mishearing and consequent misunderstanding of “laid him on the green.” Ms. Wright persisted in her idiosyncratic version because the real words were less romantic than her own (mis)interpretation in which she always imagined the Bonnie Earl o’ Moray dying beside his faithful lover Lady Mondegreen.