"The vast majority of saints venerated in the classical Sunni world were the Sufis, who were all Sunni mystics who belonged to one of the four orthodox legal schools of Sunni law.Veneration of saints eventually became one of the most widespread Sunni practices for more than a millennium, before it was opposed in the twentieth century by the Salafi movement, whose various streams regard it as "being both un-Islamic and backwards ... rather than the integral part of Islam which they were for over a millennium."