Gaudete Sunday didn't really start to become "Gaudete Sunday"-as-we-know-it-today until the modern period in general, and the nineteenth century in particular

"we must examine more carefully those observances that are considered 'traditional.' . . .  It is not enough to assume that liturgies that look archaic or anachronistic are as old as they claim to be. . . ."

     John F. Romano, "Joy in waiting?  The history of Gaudete Sunday," Medieval studies 72 (2010):  123 (75-124).  More detail from Romano to follow as time allows, but he confirms what I have long known about the Advent wreath as well.