Son of the advocate Venantius.
Archdeacon of the Church.
Soon after his ascension, his native Dalmatia was invaded by Slavs, and he worked to ransom prisoners, provide refugee assistance, and bring the Slavs themselves to the faith.
Because the churches could not be rebuilt in the war-torn area, the relics were brought to Rome; they are still housed in an oratory there.
Wrote to church leaders in Ireland concerning the proper date for celebration of Easter, and against Pelagianism.
Condemned and wrote against Monothelism.