Matilda continued her incantations; at intervals she took various items from the basket, the nature and name of most of which were unknown to the friar: but among the few which he distinguished, he particularly observed three human fingers, and an agnus dei, which she broke in pieces.
Source: wiktionary
The most common of these amulets was the agnus dei, a small wax cake, originally made out of paschal candles and blessed by the Pope, bearing the image of the lamb and flag.