12 princes, 12 tribes....
These twelve rulers, the twelve sons of Ishmael, were named Nebaioth, Kedar, Adbeel, Mibsam, Mishma, Dumah, Massa, Hadad, Tema, Jetur, Naphish, and Kedemah (See Genesis 25)
Ishmael also had a daughter named Mahalath or Bashemath (Gen 36:3). Esau married her since...