Final answer:
St. Frumentius was ordained as a bishop by Athanasius, the bishop of Alexandria.
Step-by-step explanation:
St. Frumentius was ordained as a bishop by Athanasius, the bishop of Alexandria. Frumentius was shipwrecked on the Eritrean coast and converted King Ezana of Aksum to Christianity. Ezana sent Frumentius to Alexandria to request the appointment of a bishop for Ethiopia, and Athanasius chose Frumentius for the role.