The modern Quranist movement did not emerge from a single source but arose independently in several Muslim majority countries across the twentieth century. In British India and then Pakistan, Ghulam Ahmed Pervez founded Tolu e Islam in the 1930s, arguing that centuries of hadith based jurisprudence had obscured the Quran's own social and legal teaching. In Egypt, Ahmed Subhy Mansour developed a Quran only reading from within Al Azhar, the leading center of Sunni religious learning, a position that cost him his teaching post and eventually led to his exile in the United States. A separate and more idiosyncratic strand formed around Rashad Khalifa, an Egyptian born biochemist working in Arizona, who in the 1980s claimed to have found a mathematical code based on the number nineteen embedded in the Quran's text, a claim that drew him first prominence and later hostility from mainstream Muslim organizations before his murder in 1990. The Oxford Dictionary of World Religions and the Encyclopaedia of Islam both note that established Sunni and Shia authorities have responded to Quranist positions with rejection ranging from theological refutation to, in some Muslim majority states, formal charges of apostasy, so a movement united mainly by its rejection of hadith authority has in practice produced several distinct and sometimes mutually disagreeing schools of its own.