Small, undated, and completely unassuming, MIT’s copy of Coniuratio Malignorum Spirituum was sent to offsite storage decades ago by someone who could not have known that the volume had actually been published around 1486. This incunable – the term for any book printed through the year 1500 – has proven to be the oldest book in the Vail Collection.
Coniuratio Malignorum Spirituum is essentially a handbook for performing exorcisms. The sixteen-page text, fully endorsed by the Catholic Church at the time, shared its heyday with that of the witch hunts incited by the Malleus Maleficarum, written in the same year. The Coniuratio went through more than two dozen editions before the turn of the sixteenth century. Of those editions, only two predate the Vail copy.
This particular edition, printed in Rome by Eucharius Silber (a prominent Vatican printer), was previously thought to have survived in only a single copy. Before the Vail copy surfaced, only the Senate House Library at the University of London could claim to hold one. Like so many books in the Vail Collection, the significance of the Coniuratio was brought to light only through the careful processes involved in exhaustive rare book cataloging.