 After the death of his mother, he entered with his father the abbey of Luxeuil in the Diocese of Besançon, probably about 615.Under the direction of Eustachius, Omer studied the Scriptures, in which he acquired remarkable proficiency.When King Dagobert requested the appointment of a bishop for the important city of Terouenne, the capital of the ancient territory of the Morini in Neustria, he was appointed and consecrated in 637.