The al-Saud family has held on to power by placating the kingdom's religious establishment, which is dominated by descendants of the 18th century Muslim cleric Mohammed bin Abdul Wahhab.
Another, in the 18th century, was Muhammad ibn Abd al-Wahhab, who advocated purging Islam of modern accretions and relying strictly on the Koran and hadith (the record of the prophet's words and deeds).