See p.613, note 1. For Callistus and his times, see the testimony of Hippolytus, vol. v. pp.158, 159, 160; Elucidations X., XI., XII., XIII., XIV., XV. It must be owned that the forgery is better than the genuine productions of this forerunner of the Popes of the ninth and tenth centuries. The title "Pope," in its later sense, seems not inappropriate to such a character.