Antiquities of the Jews, Book 1
The Sons of Keturah
After this Abraham married Keturah, and six sons were born to him by her, men hardy in toil and shrewd of mind: Zimran, Jokshan, Medan, Midian, Ishbak and Shuah. The sons of Shuah were Sheba and Dedan. The sons of Dedan were Letushim, Asshurim and Leummim. The sons of Medan were Ephah, Epher, Hanoch, Abida and Eldaah. Abraham arranged to settle all these sons and grandsons in colonies, and they took possession of Troglodytis, and of the country of Arabia the Happy as far as it reaches to the Red Sea. It is said of this Epher that he made war on Libya and took it, and that his grandchildren, when they settled there, called it Africa after his name. Alexander Polyhistor bears witness to what I say here; he speaks thus:
“Cleodemus the prophet, who was also called Malchus, and who wrote a history of the Jews in agreement with the history of Moses their lawgiver, relates that many sons were born to Abraham by Keturah. He even names three of them: Japheras, Sures and Japhras. From Sures the land of Assyria was named; and from the other two, Japhras and Japheras, the city of Ephra and the country of Africa took their names, because these men fought alongside Hercules when he made war on Libya and Antaeus. Hercules married the daughter of Aphranes, and by her had a son, Didorus; and Sophon was his son, from whom the barbarian people called the Sophacians took their name.”