Tahpenes' sister was Hadad's wife...

       The sister of Tahpenes (I Kings 11:19, 20) was the wife of Hadad, son of the king of Edom. Tahpenes was queen consort of Pharaoh of Egypt and a contemporary of Solomon, king of Israel. Scripture tells us that when David and Joab were at Edom, every male Edomite was slain except a youth named Hadad and some of his father's servants. The young Hadad fled to Egypt, where he was favorably received by Pharaoh, who gave him the sister of his wife in marriage. She gave birth to Genubath, who was brought up by Tahpenes among Pharaoh's children. It might be inferred that this sister died in childbirth.