From Old Town School of Music's website comes this interesting "northern song" tidbit:

Greensleeves
Harvard University's first professor of English was Francis James Child, a specialist in early English language and literature. He wrote and lectured on the works of great masters like Chaucer, Spenser and Shakespeare. He is best known though, for his five volume edition The English and Scottish Popular Ballads, published in the years 1882-89.
    Child plowed through a hundred years worth of published manuscripts and narrative collections and culled 305 titles which he considered to be original source material, a Herculean task to be sure. "The Child Ballads" collection stands as a most important historical document in the world of English language folk songs.
    "Greensleeves" is one of the most beautiful and cherished melodies in the Anglo song tradition. Francis Child notes that "It's earliest mention is in September 1580 when a Richard Jones had licensed to him 'A New Northern Dittye' of the Lady Green Sleeves."
    It is widely acknowledged that Lady Green Sleeves was at the very least a promiscuous young woman and perhaps a prostitute. The reference to the color of her sleeves indicates the grass stains from a recent rendezvous with a suitor.

Sources:
• Folk Ballads of the English Speaking World, edited by Albert B. Friedman. Viking.
• Reprints from People's Songs Bulletin, edited by Irwin Silber. Oak Publications.
Recordings on file by: Frank Hamilton, Pete Seeger.

BTW, where would we locate that rather infamous Okie, north or south? I'd say Midwest, meself...