Some of the medals or medallions reputedly Christian are stamped upon one side only, and of this class is a bronze medallion of very artistic execution discovered in the cemetery of Domitilla and now preserved in the Vatican Library. It bears two portrait types of the heads of the Apostles SS. Peter and Paul, and is assigned by Giovanni Battista de Rossi to the second century. Other medallions with the (confronted) heads of the two apostles are also known. How far the use of such medals of devotion extended in the early Church is not clear.