The unchangeable character of the Arabic language is chiefly to be attributed to the Koran, which has, from its promulgation to the present time, been regarded by all Muhammadans as the standard of religion and of literary composition. Strictly speaking, not only the history, but also the literature of the Arabs begins with Muhammad. Excepting the Mua'llakat, and other pre-Islamitic poems collected in the Hamasas of Abu Tammam and Al-Bohtori, in Ibn Kutaiba and in the Mofaddhaliat, no literary monuments that preceded his time are in existence. The Koran became, not only the code of religious and of civil law, but also the model of the Arabic language, and the standard of diction and eloquence. Muhammad himself scorned metrical rules; he claimed as an apostle and lawgiver a title higher than that of soothsayer and poet. Still, his poetic talent is manifest in numerous passages of the Koran, well known to those able to read it in the original, and in this respect the last twenty-five chapters of that book are, perhaps, the most remarkable. Although the power of the Arabs has long ago succumbed, their literature has survived, and their language is still more or less spoken in all Muhammadan countries. Europe at one time was lightened by the torch of Arabian learning, and the Middle Ages were stamped with the genius and character of Arab civilization. The great masters of philosophy, medicine, astronomy, and mathematics, viz., Al-Kindi, Al-Farabi, Ibn-Sina, Ibn-Rashid, Ibn Bajah, Razi, Al Battani, Abul Ma'shar, Al-Farghani, Al-Jaber, have been studied both in the Spanish universities and in those of the rest of Europe, where their names are still familiar under the corrupted forms of Alchendius, Alfarabius, Avicenna, Averroes, Avempace, Rhazes, Albategnius, Albumasar, Alfraganius, and Geber. Arabic literature commenced about half a century before Muhammad with a legion of poets. The seven poems suspended in the temple of Mecca, and of which more anon, were considered as the chief productions of that time. The Mussulman era begins with the Hijrah, or emigration of Muhammad from Mecca to Madinah, which is supposed to have taken place on the 20th of June, A.D. 622; and the rise, growth, and decay of Arab power, learning, and literature may be divided into three periods as follows: 1. The time before Muhammad. 2. From Muhammad and his immediate successors, viz., Abu Bakr, Omar, Othman, and Ali, through the Omaiyide and Abbaside dynasties, to the end of the Khalifate of Baghdad, A.D. 1258. 3. From the fall of Baghdad to the present time. First Period.