Born atGallese, Marinus was the son of a priest. He would become an expert on relations with the Eastern church, starting this path when he assisted as subdeacon the welcome of ambassadors of emperor Michael III in 860.[2] He was ordained as a deacon byPope Nicholas I[3] and then sent in 866 to Constantinople to discuss the religious leadership over the newlyconverted Bulgarians though the embassy was turned back at the Byzantine border.[2] Marinus was sent again in 869 as one ofpope Adrian II's legates who presided over the eighth ecumenical council in Constantinople which deposed the PatriarchPhotios I of Constantinople. His profile became popular after and some time afterwards he becamebishop of Caere, possibly to prevent that he could become archbishop of Bulgaria as one of kingBoris' favourite candidates.[2]
Marinus I was elected to succeedJohn VIII asbishop of Rome from around the end of December 882.[4] This papal election was controversial because Marinus had already beenconsecrated as bishop of Caere; at the time, a bishop was expected never tomove to anothersee. Among his first acts as pope were the restitution ofFormosus ascardinal bishop ofPortus and the anathematizing of Photius I.[6] Due to his respect forAlfred the Great (r. 871–899), he freed theAnglo-Saxons of theSchola Anglorum in Rome from tribute and taxation.[6] He also is recorded to have sent a piece of theTrue Cross to Alfred as a gift.[7] He died in May 884 and was buried in St. Peter's basilica in Rome, his successor beingAdrian III.[2]
