The situation changed after two Arab tribes named Banu Aws and Banu Khazraj arrived to Yathrib from Yemen. At first, these tribes were clients of the Jews, but toward the end of the 5th century CE, they revolted and became independent. Most modern historians accept the claim of the Muslim sources that after the revolt, the Jewish tribes became clients of the Aws and the Khazraj. William Montgomery Watt however considers this clientship to be unhistorical prior to 627 and maintains that the Jews retained a measure of political independence after the Arab revolt.