collections of fatwas by a particular scholar. Classical jurisprudence has been described as "one of the major intellectual achievements of Islam" and its importance in Islam has been compared to that of theology in Christianity. Schools of law The main Sunni schools of law (madhhabs) are the Hanafi, Maliki, Shafi'i and Hanbali madhhabs. They emerged in the ninth and tenth centuries and by the twelfth century almost all jurists aligned themselves with a particular madhhab. These four schools recognize each other's validity and they have interacted in legal debate over the centuries. Rulings of these schools are followed across the Muslim world without exclusive regional restrictions, but they each came to dominate in different parts of the world. For example, the Maliki school is predominant in North and West Africa; the Hanafi school in South and Central Asia; the Shafi'i school in Lower Egypt, East Africa, and Southeast Asia; and the Hanbali school in North and Central Arabia. The first centuries of Islam also witnessed a number of short-lived Sunni madhhabs. The Zahiri school, which is commonly identified as extinct, continues to exert influence over legal thought. The development of Shia legal schools occurred along the lines of theological differences and resulted in formation of the Twelver, Zaidi and Ismaili madhhabs, whose differences from Sunni legal schools are roughly of the same order as the differences among Sunni schools. The Ibadi legal school, distinct from Sunni and Shia madhhabs, is predominant in Oman. The transformations of Islamic legal institutions in the modern era have had profound implications for the madhhab system. Legal practice in most of the Muslim world has come to be controlled by government policy and state law, so that the influence of the madhhabs beyond personal ritual practice depends on the status accorded to them within the national legal system. State law codification commonly utilized the methods of takhayyur (selection of rulings without restriction to a particular madhhab) and talfiq (combining parts of different rulings on the same question). Legal professionals trained in modern law schools have largely replaced traditional ulema as interpreters of the resulting laws. Global Islamic movements have at times drawn on different madhhabs and at other times placed greater focus on the scriptural sources rather than classical jurisprudence. The Hanbali school, with its particularly strict adherence to the Quran and hadith, has inspired conservative currents of direct scriptural interpretation by the Salafi and