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 by Pope Nicholas I[3] and then sent in 866 to Constantinople to discuss the religious leadership over the newly converted Bulgarians though the embassy was turned back at the Byzantine border.
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' favourite candidates.
[4][3] 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.
[6] Due to his respect for Alfred the Great (r. 871–899), he freed the Anglo-Saxons of the Schola Anglorum in Rome from tribute and taxation.