Augustin Calmet conducted extensive research on the topic in his work titled "Traité sur les apparitions des esprits et sur les vampires ou les revenans de Hongrie, de Moravie, &c." (1751) in which he relates the rumors of men at the time: Calmet compares the ideas of the Greek and Egyptian ancients and notes an old belief that magic could not only cause death but also evoke the souls of the deceased as well. Calmet ascribed revenants to sorcerers who sucked the blood of victims and compares instances of revenants mentioned in the twelfth century in England and Denmark as similar to those of Hungary, but "in no history do we read anything so usual or so pronounced, as what is related to us of the vampires of Poland, Hungary, and Moravia."