One of the most famous of all talismans, and used as a magical formula by the Gnostics in Rome for invoking the aid of beneficient spirits against disease, misfortune and death. Sammonieus, the celebrated Gnostic physician; instructed that the letters of this magical triangle which he used for curing agues and fevers, were to be written on paper, folded into the shape of a cross, worn for nine days suspended from the neck, and, before sunrise, cast behind the patient into a stream running eastward. It was also a most popular charm in the middle ages. During the Great Plague, 1665, great numbers of these amulets were worn as supposed safeguards against infection.