section_path: Medieval Middle East/Islamic caliphate
section_name: Islamic caliphate
paragraph_text: Islamic caliphate
  
  While the Byzantine Roman and Sassanid Persian empires were both weakened by warfare (602–628), a new power in the form of Islam grew in the Middle East. In a series of rapid Muslim conquests, Arab armies, led by the Caliphs and skilled military commanders such as Khalid ibn al-Walid, swept through most of the Middle East, taking more than half of Byzantine territory and completely engulfing the Persian lands. In Anatolia, they were stopped in the Siege of Constantinople (717–718) by the Byzantines, who were helped by the Bulgarians.
  
  The Byzantine provinces of Roman Syria, North Africa, and Sicily, however, could not mount such a resistance, and the Muslim conquerors swept through those regions. At the far west, they crossed the sea taking Visigothic Hispania before being halted in southern France in the Battle of Tours by the Franks. At its greatest extent, the Arab Empire was the first empire to control the entire Middle East, as well three-quarters of the Mediterranean region, the only other empire besides the Roman Empire to control most of the Mediterranean Sea. It would be the Arab Caliphates of the Middle Ages that would first unify the entire Middle East as a distinct region and create the dominant ethnic identity that persists today. The Seljuq Empire would also later dominate the region.
  
  Much of North Africa became a peripheral area to the main Muslim centres in the Middle East, but Iberia (Al-Andalus) and Morocco soon broke away from this distant control and founded one of the world's most advanced societies at the time, along with Baghdad in the eastern Mediterranean. Between 831 and 1071, the Emirate of Sicily was one of the major centres of Islamic culture in the Mediterranean. After its conquest by the Normans the island developed its own distinct culture with the fusion of Arab, Western, and Byzantine influences. Palermo remained a leading artistic and commercial centre of the Mediterranean well into the Middle Ages.
  
  Africa was reviving, however, as more organized and centralized states began to form in the later Middle Ages after the Renaissance of the 12th century. Motivated by religion and conquest, the kings of Europe launched a number of Crusades to try to roll back Muslim power and retake the Holy Land. The Crusades were unsuccessful but were far more effective in weakening the already tottering Byzantine Empire. They also rearranged the balance of power in the Muslim world as Egypt once again emerged as a major power.