These doctrinal fissures in Islam were paralleled by the disruption of political unity. The first formal split occurred after the accession of the Abbasides. A member of the deposed Ommeyyad family fled to Spain, where he set up a rival caliphate at Cordova, recognized as lawful not only by the Spanish Moslems, but by the Berbers of North Africa. Later on another caliphate was set up in Egypt--the Fatimite caliphate, resting its title on descent from Mohammed's daughter Fatima. As for the Abbaside caliphs of Bagdad, they gradually declined in power, until they became mere puppets in the hands of a new racial element, the Turks.
Before describing that shift of power from Neo-Arab to Turkish hands which was so momentous for the history of the Islamic world, let us first consider the decline in cultural and intellectual vigour that set in concurrently with the disruption of political and religious unity during the later stages of the Neo-Arab period.
The Arabs of Mohammed's day were a fresh, unspoiled people in the full flush of pristine vigour, eager for adventure and inspired by a high ideal. They had their full share of Semitic fanaticism, but, though fanatical, they were not bigoted, that is to say, they possessed, not closed, but open minds. They held firmly to the tenets of their religion, but this religion was extremely simple. The core of Mohammed's teaching was theism _plus_ certain practices. A strict belief in the unity of God, an equally strict belief in the divine mission[2] of Mohammed as set forth in the Koran, and certain clearly defined duties--prayer, ablutions, fasting, almsgiving, and pilgrimage--these, and these alone, constituted the Islam of the Arab conquerors of the Eastern world.
So simple a theology could not seriously fetter the Arab mind, alert, curious, eager to learn, and ready to adjust itself to conditions ampler and more complex than those prevailing in the parched environment of the desert. Now, not only did the Arabs relish the material advantages and luxuries of the more developed societies which they had conquered; they also appreciated the art, literature, science, and ideas of the older civilizations. The effect of these novel stimuli was the remarkable cultural and intellectual flowering which is the glory of Saracenic civilization. For a time thought was relatively free and produced a wealth of original ideas and daring speculations. These were the work not only of Arabs but also of subject Christians, Jews, and Persians, many of them being heretics previously depressed under the iron bands of persecuting Byzantine orthodoxy and Magism.