Pope Sixtus I, also spelled Xystus, a Roman of Greek descent, was the bishop of Rome from c. 115 to his death. He succeeded Alexander I and was in turn succeeded by Telesphorus. His feast is celebrated on 6 April.

Pope Alexander I was the bishop of Rome from c. 107 until his death c. 115. The Holy See's Annuario Pontificio (2012) identifies him as a Roman who served from 108 or 109 to 116 or 119. Some believe he suffered martyrdom under the Roman emperor Trajan or Hadrian.