Jurisconsults. Imams and lawyers. Traditionists. Alchemists. Astronomers. Grammarians. Geographers and travellers. Historians. Lexicographers, biographers and encyclopaedists. Writers on natural history. Philologists. Philosophers. Physicians. Poets. Collectors and editors of poems. Translators. The Omaiyide Khalifs. The Abbaside Khalifs. The Spanish Khalifs. During the latter part of the first century of the Hijrah (July, 622--July, 719), the first persons of note in the Muhammadan world after Muhammad and his immediate successors were probably the seven jurisconsults, viz., Obaid Allah, Orwa, Kasim, Said, Sulaiman, Abu Bakr and Kharija, who all lived at Madinah about the same time; and it was from them, according to Ibn Khallikan, that the science of law and legal decisions spread over the world. They were designated by the appellation of the Seven Jurisconsults, because the right of giving decisions on points of law had passed to them from the companions of Muhammad, and they became publicly known as Muftis. These seven alone were acknowledged as competent to give Fatmas, or legal decisions. They died respectively A.D. 720, 712, 719, 710, 725, 712 and 718. The jurisconsults were followed by the doctors of theology and law, or, as they were styled, Imams, or founders of the four orthodox sects. Now, among the Sunni Muslims an Imam may be described as a high-priest, or head, or chief in religious matters, whether he be the head of all Muhammadans--as the Khalifah--or the priest of a mosque, or the leader in the prayers of a congregation. This title, however, is given by the Shias only to the immediate descendants of Ali, the son-in-law of the Prophet, and they are twelve in number, Ali being the first. The last of them, Imam Mahdi, is supposed to be concealed (not dead), and the title which belongs to him cannot, they conceive, be given to another. But among the Sunnis it is a dogma that there must always be a visible Imam or father of the Church. The title is given by them to the four learned doctors who were the exponents of their faith, viz., Imams Hanifa, Malik, Shafai and Hanbal. Of these, Imam Hanifa, the founder of the first of the four chief sects of the Sunnis, died A.D. 767. He was followed by Imam Malik, Imam Shafai, and Imam Hanbal, the founders of the other three sects, who died A.D. 795, 820 and 855 respectively. From these four persons are derived the various codes of Muhammadan jurisprudence. They have always been considered as the fundamental pillars of the orthodox law, and have been esteemed by Mussulmans as highly as the fathers of the Church--Gregory, Augustine, Jerome and Chrysostom--have been appreciated by Christians. Of these four sects, the Hanbalite and Malikite may be considered as the most rigid, the Shafaite as the most conformable to the spirit of Islamism, and the Hanifite as the wildest and most philosophical of them all.