The Mirror of Simple Souls, one of the most important mystical treatises of the late Middle Ages, was also one of the most resilient. Written in Old French by a laywoman, Marguerite Porete, at the end of the thirteenth century, it was condemned as heretical twice shortly after it was written: first in Valenciennes sometime between 1297 and 1305, and again in Paris in 1310, when its author was also condemned and burned at the stake. Yet the Mirror escaped destruction and continued to circulate anonymously, surviving not only in French but also in English, Latin, and Italian translations.

In the conclusion to his 2010 article ‘New Light on the Mirror of Simple Souls’, Robert E. Lerner, commenting on this resilience, posited that rather than being relatively thin, the Mirror of Simple Souls's late medieval circulation was instead quite robust. Tallying up the surviving French, Middle English, Latin, and Italian manuscripts, and noting evidence for several other now-lost copies, he observed in his closing sentence that ‘it appears as if dozens of copies of the Mirror were bobbing up continually in the seas of late medieval western Europe like unsinkable corks’.

This remark remains entirely on point. Evidence for further copies drifting around Europe in the fifteenth century has continued to appear in the years since Lerner's article. But while plenty of rumors of these Mirrors’ existence have been found, one thing which has remained elusive for over thirty years is a new, full manuscript copy of the Mirror, in any of its linguistic versions. A few fragments and excerpts from lost Mirrors have surfaced here and there, but new full copies have long been absent.

This long drought has now broken, however. Proving once again the aptness of Lerner's observation, not one but two new corks have bobbed to the surface in the Latin manuscript tradition of the Mirror (Speculum simplicium animarum), offering crucial new insights into the Mirror's fortunes in the ‘seas’ of late medieval Europe.