The ancient kingdom of Ethiopia corresponded not to what is Ethiopia today, but to Nubia, the southern part of Egypt and the northern part of the Sudan. The king of this kingdom was regarded as too sacred too deal with the secular functions of government and these were managed on his behalf by the queen-mother, who bore the title "Candace."
Bible: The Conversion of the Ethiopian
And the angel of the Lord spoke to Philip, saying, Get up, and go toward the south unto the way that goes down from Jerusalem to Gaza, which is desert. And he got up and went: and, behold, a man of Ethiopia, an eunuch of great authority under Candace queen of the Ethiopians, who had the charge of all her treasure, and had come to Jerusalem to worship, Was returning, and sitting in his chariot read Isaiah the prophet. Then the Spirit said to Philip, Go near, and stay close to this chariot. And Philip ran up to him, and heard him reading the prophet Isaiah, and said, Do you understand what you are reading? And he said, How can I, except someone should guide me? And he invited Philip to come up and sit with him. The place of the scripture which he read was this,
“He was led as a sheep to the slaughter; and like a lamb dumb before his shearer, so opened he not his mouth: In his humiliation his judgment was taken away: and who shall declare his generation? for his life is taken from the earth.”
And the eunuch answered Philip, and said, I ask you, of whom is the prophet speaking? of himself, or of some other man? Then Philip opened his mouth, and began at the same scripture, and preached to him Jesus. And as they went on their way, they came to some water: and the eunuch said, See, here is water; what keeps me from being baptized? And Philip said, If you believe with all your heart, you may. And he answered and said, I believe that Jesus Christ is the Son of God. And he commanded the chariot to stop: and they both went down into the water, both Philip and the eunuch; and Philip baptized him. And when they came up out of the water, the Spirit of the Lord caught away Philip, and the eunuch saw him no more: but he went on his way rejoicing. But Philip was found at Azotus: and passing through he preached in all the cities, till he came to Caesarea.