Pope Sixtus I

Pope Sixtus I (Greek: Σίξτος), also spelled Xystus, a Roman of Greek descent, was the bishop of Rome from c. 117 or 119 to his death c. 126 or 128. He succeeded Alexander I and was in turn succeeded by Telesphorus. His feast is celebrated on 6 April.

Source: Wikipedia — https://en.wikipedia.org/wiki/Pope_Sixtus_I