In Paris in 1310, twenty-one theologians from the University of Paris condemned the Mirror of Simple Souls as heretical. While three errors taken from the Mirror were cited as evidence of its heresy, the reasoning behind this condemnation and the specific opinions of the theologians are not recorded. Although its author, Marguerite Porete, was burned at the stake for composing and circulating it, the Mirror managed to survive and circulate anonymously in a number of languages, and was positively received by a variety of religious circles in the late Middle Ages. This contrast between the theologians’ condemnation and the positive reception of the Mirror has often led to the impression that its condemnation at Paris in 1310 was merely a blip on the radar of the Mirror’s otherwise ‘orthodox’ reception. But evidence from the Mirror’s Latin version shows a parallel tradition of continued opposition and re-condemnation, and one text in particular, found in a fifteenth-century Paduan manuscript, provides a detailed, systematic attack on the Mirror by a canon lawyer who, entirely unaware of the Mirror’s history, genuinely believed it to be a dangerous heretical text. This paper will examine the text’s contents in detail, allowing insight into exactly what doctrines in the Mirror were considered alarming, which areas of canon law and Scripture it was believed to contravene, and what kind of rhetoric and imagery was employed against it.