In Dr. Carleton Brown's admirable study of the narrative which supplied the basis for The Prioresses Tale he pointed out that Chaucer made use of a thirteenth-century exemplum of a Miracle of our Lady. Although the earliest extant versions are of the thirteenth century, the story had its origin before 1200. There is, however, a striking similarity between the details of Chaucer's poem and the Latin exemplum C vi, which Dr. Brown has printed from a collection of Miracles of the Virgin in Sidney Sussex College, Cambridge, MS. A.5.10, Lib. ii, Cap 87, written in the fifteenth century. This post-Chaucerian version offers a number of points for comparison: a little boy passed twice a day through the Jewry singing his antiphon. So in Chaucer: Twies a day it passed thurgh his throte, As I have seyd, thurghout the Juerie, This litel child, as he cam to and fro, Ful murily than wolde he synge and crie O alma redemptoris everemo.