The situation changed after the arrival from Yemen of two new Arab tribes named Banu Aus (or Banu 'Aws) and Banu Khazraj. At first, these tribes were allied with Jewish rulers, but later they revolted and became independent.[14] Toward the end of the 5th century,[15] the Jewish rulers lost control of the city to Banu Aus and Banu Khazraj. The Jewish Encyclopedia states that they did so "by calling in outside assistance and treacherously massacring at a banquet the principal Jews", Banu Aus and Banu Khazraj finally gained the upper hand at Medina.[12]