Many of the strict and unique practices in Saudi Arabia mentioned above come from Wahhabism, the official and dominant form of Sunni Islam in Saudi Arabia, named after the preacher and scholar Muhammad ibn Abd al-Wahhab. Proponents consider the name derogatory, preferring the term Salafiyya, after the early Muslims known as the Salaf. This interpretation is often described as 'puritanical', 'intolerant' or 'ultra-conservative', however proponents believe its teachings seek to purify the practise of Islam of any innovations or practices that deviate from the seventh-century teachings of the Islamic prophet Muhammad and his companions. According to one anti-Wahhabi source (Stephen Schwartz), no more than 40% of Saudi nationals consider themselves Wahhabis.