Papa Sixtus I (au Xystus) alikuwa Papa kuanzia takriban 117/119 hadi kifo chake takriban 126/128[1][2]. Alitokea Roma, Italia na jina la baba yake lilikuwa Pastor[3].
According to the Liberian Catalogue of popes, he served the Church during the reign of Hadrian "from the consulate of Niger and Apronianus until that of Verus III and Ambibulus", that is, from 117 to 126. Eusebius states in his Chronicon that Sixtus I was pope from 114 to 124, while his Historia Ecclesiastica, using a different catalogue of popes, claims his rule from 114 to 128. All authorities agree that he reigned about ten years.
Martyrologium Romanum: ex Decreto Sacrosancti oecumenici Concilii Vaticani II instauratum auctoritate Ioannis Pauli P.P. II promulgatum, Romae 2001, ISBN 8820972107
Chapman, John. Studies on the Early Papacy. Port Washington, NY: Kennikat Press, 1971. ISBN 978-0-8046-1139-8.
Fortescue, Adrian, and Scott M. P. Reid. The Early Papacy: To the Synod of Chalcedon in 451. Southampton: Saint Austin Press, 1997. ISBN 978-1-901157-60-4.
Jowett, George F. The Drama of the Lost Disciples. London: Covenant Pub. Co, 1968. OCLC 7181392
Loomis, Louise Ropes. The Book of Popes (Liber Pontificalis). Merchantville, NJ: Evolution Publishing. ISBN 1-889758-86-8.