Genesis 25:1-6

Abraham again took a wife, and her name was Keturah. And she bore him Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. Jokshan begot Sheba and Dedan. And the sons of Dedan were Asshurim, Letushim, and Leummim. And the sons of Midian were Ephah, Epher, Hanoch, Abidah, and Eldaah. All these were the children of Keturah. And Abraham gave all that he had to Isaac. But Abraham gave gifts to the sons of the concubines which Abraham had; and while he was still living he sent them eastward, away from Isaac his son, to the country of the east.