The Buyids were initially Zaidi as were the Banu Ukhaidhir rulers of al-Yamama in the 9th and 10th centuries. The leader of the Zaydi community took the title of Caliph. As such, the ruler of Yemen was known as the Caliph, al-Hadi Yahya bin al-Hussain bin al-Qasim ar-Rassi Rassids (a descendant of Hasan ibn Ali the son of Ali) who, at Sa'dah, in 893–7 CE, founded the Zaydi Imamate, and this system continued until the middle of the 20th century, when the revolution of 1962 CE deposed the Zaydi Imam. The founding Zaidism of Yemen was of the Jarudiyya group; however, with increasing interaction with Hanafi and Shafi'i rites of Sunni Islam, there was a shift from the Jarudiyya group to the Sulaimaniyya, Tabiriyya, Butriyya or Salihiyya groups. Zaidis form the second dominant religious group in Yemen. Currently, they constitute about 40–45% of the population in Yemen. Ja'faris and Isma'ilis are 2–5%. In Saudi Arabia, it is estimated that there are over 1 million Zaydis (primarily in the western provinces).