Perhaps the most common Arab characteristic is adherence to the Islamic faith. Muslim Arabs comprize about 93 percent of the Arab population and belong to several different sects including Shia (Ithna Ashari and Ismaili), Alawi, Zaidi, and Sunni, which is the largest. The other 7 percent of Arabs are largely Christian or Druze.
The link between Arabs and Islam has deep historical roots. It was among Arabs early in the seventh century that Mohammed preached the tenets of Islam. Mohammed's successors quickly spread the word of Allah into Southwest Asia, across North Africa and into Spain, into Persia, Afghanistan, and Central Asia, and to the east coast of Africa. Wherever Muslims went, they left elements of Arab culture along with their religion. The cultures of the assimilated territories, which included Christian, Jewish, and Zoroastrian populations, were not only influenced by the Arab invaders and their religion, but, in turn, substantially influenced the nature of Arab culture.
The conquered populations were subjugated politically, but their administrative skills, crafts, arts, and worldviews gradually transformed their conquerors. This transformation of Arab identity and tradition has been a continuing process for over 1,300 years. Pre-Islamic poetry indicates that in the year 600 "Arab" referred to the Semitic-speaking tribes of the Arabian Peninsula. Quranic usage and other Arabian sources suggest that the word referred primarily to the pastoral Bedouin tribes of the region. Even though camel-herding pastoral nomads were only a minority during Mohammed's lifetime, it seems clear that Arabs were an important social and political force. Their rich oral literature, especially their poetry, and their rejection of authoritarian political forms presented a powerful cultural ideal. Nevertheless, townspeople and others often used the term "Arab" in a pejorative sense. Southern Arabians, both farmers and urban residents, probably did not at first regard themselves as Arab. They probably only adopted this identity when there were political and economic advantages to doing so after the adoption of Islam.
The early Islamic period was a time when Arab identity meant that one belonged to an all-encompassing patrilineal descent system. Membership in an Arab descent group brought recognition, honor, and certain privileges, such as exemption from some taxes. The significance attributed to one s genealogical ties has not prevented Arab societies from assimilating non-Arabs into Arab society, a practice that has remained important throughout Arab history. In the first years after the Arab conquest, it was common to convert to Islam and become an Arab at the same time by forming a relationship with an Arab tribe. Later, converting to Islam and acquiring Arab identity became separate processes. Islamization continued, but it was no longer tied to Arabization.
Muslim Arab leaders created great empires that lasted hundreds of years. Following Mohammed, the Umayyid dynasty was established in Damascus in 661 and lasted until 750. Religious and ethnic minorities were given a large measure of self-rule under Umayyid domination. The succeeding ʿAbbāsid dynasty ruled the Muslim world from Baghdad, its capital, for nearly 500 years, of which the first 200 (750-950) are called the Golden Age of Arab civilization.
Arab rulers brought intellectual Jews, Christians, Greeks, Persians, and Indians to Baghdad and other centers of learning during the ʿAbbāsid dynasty. These foreign intellectuals contributed elements from their own cultures to the development of Arab culture. The works of Plato and Aristotle were translated from Greek into Arabic before they were translated into other European languages. Indian scientists brought the concept of "zero" to the Arabs, who combined it with Arabic numerals and transmitted the mathematical systems of algebra, geometry, and trigonometry to Europe. There are also many other important scientific discoveries that can be traced to the ʿAbbāsid dynasty. ʿAbbāsid scientists disproved Euclid's theory that the eye emanates rays, ʿAbbāsid chemists introduced such concepts as "alkali" and "alcohol," and ʿAbbāsid medical scholars compiled the world's first medical encyclopedia. What was happening throughout the world at that time was being recorded and passed on to later civilizations by Arab historians.
The ʿAbbāsid Empire was declining by the thirteenth century. Largely because of European colonization of North and South America, European trade with the Arab world virtually stopped and did not resume until the opening of the Suez Canal in 1869. The outlying provinces of the empire were the first to break away. Then, the Arabs were pushed out of Spain. Invading Turks and Mongols from the north destroyed not only the cities and towns in their path, but also irrigation systems. The Arab economy never recovered from the destruction. By the sixteenth century, Seljuk and Ottoman Turkish invaders conquered the remaining Arab territories; they ruled until World War I, when the Turkish Empire in turn disintegrated.