Genesis 25:1-6

Abraham took another wife, whose name was Keturah. She gave birth to Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. Jokshan was the father of Sheba and Dedan. The sons of Dedan were Asshurim, Letushim, and Leummim. The sons of Midian were Ephah, Epher, Hanoch, Abida, and Eldaah. All these were the sons of Keturah. Now Abraham gave everything that he had to Isaac; but to the sons of his concubines [Hagar and Keturah], Abraham gave gifts while he was still living and he sent them to the east country, away from Isaac his son [of promise].