Editing Pope Marinus I (section)

===Diplomat to the East===
Born at [[Gallese]], 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.<ref name="ThePapacy">{{cite book |editor1-last=Levillain |editor1-first=Philippe |editor2-last=O'Malley |editor2-first=John W. |title=The Papacy: Gaius-Proxies |date=2002 |publisher=Psychology Press |isbn=978-0-415-92230-2 |pages=969–970 |url=https://books.google.com/books?id=7VDcmDeLuV4C |access-date=25 March 2024 |language=en |chapter=Marinus I}}</ref> He was ordained as a deacon by [[Pope Nicholas I]]<ref name= McBrien>{{cite book|url=https://books.google.com/books?id=stYqDs2Me_4C|first=Richard P.|last= McBrien|title=Lives of the Popes: The Pontiffs from St. Peter to Benedict XVI| publisher=HarperCollins|year=2000|page= 142|isbn=9780060878078}}</ref> and then sent in 866 to Constantinople to discuss the religious leadership over the newly [[Christianization of Bulgaria|converted Bulgarians]] though the embassy was turned back at the Byzantine border.<ref name="ThePapacy" /> Marinus was sent again in 869 as one of [[pope Adrian II]]'s legates who presided over the eight ecumenical council in Constantinople which deposed the Patriarch [[Photios I of Constantinople]]. His profile became popular after and some time afterwards he became [[bishop of Caere]], possibly to prevent that he could become archbishop of Bulgaria as one of king [[Boris I of Bulgaria|Boris]]' favourite candidates.<ref name="ThePapacy" />

On three separate occasions, he had been employed by the three popes who preceded him as [[papal legate|legate]] to [[Constantinople]], his mission in each case having reference to the controversy started by Patriarch [[Photios I of Constantinople]].<ref name="EB1911"/><ref name= McBrien/> In 882, he was sent on behalf of [[Pope John VIII]] to Duke [[Athanasius of Naples]] to warn him not to trade with the [[Muslims of southern Italy]].<ref>{{cite book|author1=Philippe Levillain|title=The Papacy: Gaius-Proxies|date=1 Jan 2002|publisher=Psychology Press|isbn=9780415922302|page=969|edition=illustrated}}</ref> During that time, he also served as treasurer to the Holy See.<ref name="ThePapacy" />