Frumentius was a Bishop known as the person who started the Ethiopian Orthodox Church and who brought Christianity to Ethiopia.
Frumentius was born in the 4th Century in Tyre which is now Lebanon. Frumentius and his brother Edesius were shipwrecked in Eritrea. Everyone else on the ship was killed by the people there but Frumentius and Edesius were captured and sold into slavery. They became slaves of Ousanas, the King of the tribe of Axum. Ousanas freed them before his death and his widow hired them to tutor her son Ezana, King of Axum.
While teaching Ezana, Frumentius tried to convince as many people as he could to become Christian. Once Ezana was an adult both Frumentius and his brother Edesius left Ethiopia. Edesius went back home to Tyre but Frumentius went to Egypt to convince Athanasias the creator of the Athanasian Creed to appoint missionaries to Axum. So Athanasius appointed Frumentius as a bishop. Frumentius went back to Ethiopia this time with Christian priests to start Churches and to convince people there to become Christians. Frumentius even managed to get King Ezana to convert to Christianity. When the Roman Empire told Ezana to replace Frumentius with another bishop, because Frumentius didn’t believe in the Nicene Creed, Ezana said no.
In Ethiopia, the Orthodox Church says that Frumentius is a Saint and they call him Saint Frumentius.