A Fifteenth Century Word Game

The Book of Brome (Beinecke MS 365, f. 1v) includes a word game that relies on a simple cypher (and, alas, isn’t very nice to the ladies). This puzzle provides some insight on how the literate classes entertained themselves and is not at all dissimilar to the cryptoquote puzzle in our local paper. I've included a short discussion and hint for its solution under the cut.