Bishop of Rome from about 254 to 257, followed Lucius I. He withdrew from church fellowship with Cyprian and certain Asiatic bishops on account of their views as to the necessity of rebaptizing heretics (Euseb. vii. 5; Cypr. Epp. 75). He is also mentioned as having insisted on the restoration of the bishops of Merida and Astorga, who had been deposed for unfaithfulness during persecution but afterwards had repented. He is commemorated on August 2. His successor was Sixtus II.