According to His Gadl (hagiography), Abba Garima was the son of Emperor of Rome (Byzantium), Masfeyanos, and his wife, Sefengeya. His mother bore him through the intercession of the Virgin Mary after fifteen years of barrenness.
He was sent to study theology and then he was appointed deacon, but later, on his father’s death, became king against his will. After he had ruled seven years, he was summoned by Abba Pantalewon and, with the help of the Archangel Gabriel, was able to reach Aksum in three hours during the reign of Alameda. There he joined Pantalewon and remained with his community for some years until they parted company, when he went to Madara and founded a monastery. He stayed there for twenty-three years performing miracles, driving out demons, and tending to the sick.
Among his amazing miracles one is written as follows, one day he sowed wheat at dawn, and reaped it in the evening and some of it he offered as an offering; and on the following day he took the remainder up to the threshing floor, and he trod out the sheaves of wheat, and obtained there seventy-seven measures of grain.
Having finished his good course, our Redeemer appeared unto him, and promised him that [He would forgive the sins of] those who call upon his name, and celebrate his commemoration. And straightway he was caught up in a shining cloud and disappeared. Some say Garima died on 17 Sanie (24 June). The Emperor Gabra-Masqal is reputed to have built him a church there, which he endowed liberally.
Source: • Synaxarium: The book of the saints of the Ethiopian Church.