Bede,
Lives of the holy abbots of Wearmouth and Jarrow
(8th century)
“ Ceolfrid, whom Benedict made abbot, had been his most zealous assistant from the first foundation of the former monastery, and had gone with him at the proper time to Rome, for the sake of acquiring instruction, and offering up his prayers. At which time also he chose priest Easterwine to be the abbot of St. Peter's monastery, that with the help of this fellow soldier he might sustain a burden otherwise too heavy for him. And let no one think it unbecoming that one monastery should have two abbots at once. ”
