Mohammed Osman

A Slow Process. Hearing that Muslims conquered territory "from the Atlantic to the borders of China," many people reading about Muslim history often wrongly imagine that this huge region instantly became "Islamic." The rapid conquests led to the idea that Islam spread by the sword, with people forced to become Muslims. In fact, however, the spread of Islam in these vast territories took centuries, and Muslims made up a small minority of the population for a long time. In other words, the expansion of territory under Muslim rule happened very rapidly, but the spread of Islam in those lands was a much slower process. The paragraphs below explain how and when that happened.

"Let there be no compulsion in religion." The Qur’an specifies, "Let there be no compulsion in religion" (2: 256). This verse states that no person can ever be forced to accept religion against their will. It tells Muslims never to force people to convert to Islam. Anyone who accepts Islam under pressure might not be sincere, and conversion in name only is useless to them, and harmful to members of the faith community.

Prophet Muhammad set a precedent as the leader of Madinah. Under his leadership, the Muslims practiced tolerance towards those of other religions. They were parties to the Constitution of Madinah and to treaties with the Muslims, discussing religious ideas with the Jews, Christians and polytheists (believers in many gods). The Qur’an records some of the questions that they put to Muhammad about Islam. Later Muslim leaders were required to be tolerant, based on the authority of both the Qur’an (in this and many other verses), and the Sunnah, or example of Muhammad. With few exceptions, Muslim leaders have adhered to it over time.

Becoming Muslim. To accept Islam, a person only has to make the profession of faith (shahada) in front of two or more witnesses. Even after a person has accepted Islam, he or she may take a long time to learn and apply its practices, going through many different stages or levels of understanding and practice over time. As Islam spread among large populations, this process was multiplied across a whole population. Different individuals and social classes may have different understandings of Islam at the same time. Also, many local variations and pre-Islamic customs remained, even after societies had been majority Muslim for a long time. This has been a source of diversity among Muslim cultures and regions.

The Process of Conversion. The Prophet Muhammad preached Islam at Makkah and Madinah in Arabia for about twenty-three years. For the first ten years (612 to 622 CE), he preached publicly at Makkah. After the migration to Madinah he preached only in his own house—which was the first masjid—only to people who came to hear him. Preaching in houses or in the masjid became the pattern in Islam.

The first two khalifahs required most of the inhabitants of Arabia who had been pagans to affirm their loyalty as Muslims. Christian and Jewish communities were allowed to continue practicing their faiths. In Yemen there are still Jewish communities. Outside Arabia, however, the khilafah did not force non-Arabs to become Muslims. Historians are surprised that they did not even encourage them to become Muslims. Only Khalifah ‘Umar ibn ‘Abd al-‘Aziz (ruled 717–720) made an effort to encourage people to accept Islam, and sent out missionaries to North Africa and other areas. During the early khilafah (632–750), non-Arabs began to accept Islam of their own free will. New Muslims migrated to Muslim garrison cities, to learn about Islam and possibly to get jobs and associate themselves with ruling groups. Whatever their reasons their actions became more common over the years, and expanded the Muslim population. These migrants became associates, or mawali, of Arab tribes. The mawali also tried to convince their relatives and members of their ethnic group to become Muslims. Some migrant Arab and mawali families made important contributions in preserving and spreading Islamic knowledge. They became scholars of Islamic law, history, literature and the sciences. In this way, Islam spread in spite of political rulers, not because of them.

During the years of the Umayyad khalifahs from 661–750 CE, the overwhelming majority of non-Arab population of the Umayyad—which stretched from Morocco to China—were not Muslims. Toward the end of that time, the North African Berbers became the first major non-Arab group to accept Islam.

Within a few centuries, Christianity disappeared almost completely from North Africa—as it did from no other place in the Muslim world. Jews remained as a small minority, with many living in Muslim Spain. Iranians of Central Asia were the second major movement in the spread of Islam, beginning in about 720 CE. Both of these early groups of converts caused problems for the central government. In North Africa, Berbers set up an independent khalifah, breaking the political unity of Islam. In in Central Asia, the revolution arose that replaced the Umayyad with the Abbasid dynasty. After this time, Islam was no longer the religion of a single ethnic group or of one ruling group.

Developing a Muslim culture. In the central lands, the gradual spread of Islam is difficult to trace. Some scholars, such as Richard Bulliet, think that in Egypt, few Egyptians had become Muslims before the year 700, and Islam reached 50 percent of the population in the 900s, three hundred years after the arrival of Islam. By about 1200, Muslims were more than 90 percent of the population. In Syria, Islam spread even more slowly. There, the 50-percent mark was not reached until 1200, nearly six hundred years after the arrival of Islam. Iraq and Iran probably reached a Muslim majority by around 900 CE, like Egypt. In much of Spain and Portugal, Islam became established between 711 and about 1250. After the Reconquista by Spanish Catholics was completed in 1492, and many Muslims and Jews were expelled from Spain, Islam continued to exist until after 1600. Islam may never have been the majority faith during the 700 years of Muslim rule. Spain, Portugal and Sicily are the only places where which Islam has ever been driven out.

In the East, Muslim law treated Zoroastrians, Buddhists, and Hindus just as it treated Jews and Christians. Muslim rulers offered them protection of life, property, and freedom of religious practice in exchange for the payment of a tax, as an alternative to military service. In Sind (India), the Buddhist population seems to have embraced Islam over about two centuries (712–900). Buddhism disappeared entirely. Hinduism in Sind declined much more slowly than Buddhism.

All of the lands described above were territories under Muslim rule. After the decline of unified Muslim rule, Islam spread to lands outside its boundaries. Anatolia

(or Asia Minor), which makes up most of modern Turkey, came after 1071 under the rule of Turkish tribesmen who had become Muslims. Islam spread gradually for centuries after that.

When the Ottoman Turks reached south-eastern Europe in the mid fourteenth century, most Albanians and Bosnians and some Bulgarians became Muslims. Beginning in the fifteenth century, however, Islam did not spread rapidly in this area, perhaps because the population resented or disliked the centralized government of the Ottoman Empire. Strong feelings about religion and ethnicity in the region may also have been a cause.

Continuing Spread. Beginning in 1192, other Muslim Turkish tribesmen conquered parts of India, including the area of present-day Bangladesh. The number of Muslims there gradually increased in India from that time. The people of Bangladesh were Buddhists, and, beginning about 1300, they—like the Buddhists of Sind—rapidly embraced Islam, becoming a Muslim majority in that region. Elsewhere in India, except for Punjab and Kashmir in the north-west, Hinduism remained the religion of the majority.

In South India and Sri Lanka, traders and Sufis, or mystical followers of Islam, spread Islam and carried it to Southeast Asia by 1300 CE. Over the next two centuries in today’s Indonesia—the Spice Islands—Islam spread from Malaysia to Sumatra and reached the Moluccas in eastern Indonesia. Entering a land where Buddhism, Hinduism and traditional faiths of the island people existed, it took several centuries before practice of Islam became established as it was practiced in other Muslim lands. In Central Asia, Islam gradually spread to the original homelands of the Turks and Mongols, until it was the main religion of nearly all Turkic-speaking peoples. Islam spread into Xinjiang, the western part of China, where it was tolerated by the Chinese empire. Much earlier, in the 8th and 9th centuries, a group of ethnic Chinese Han had accepted Islam. These groups continue to practice Islam today. Islam spread to China through the seaports such as Guanzhou, where the earliest Chinese masjid exists.

Africa. Before 1500, Islam spread widely in sub-Saharan Africa. The first town south of the Sahara that became majority Muslim was Gao on the Niger River in Mali before 990, when a ruler accepted Islam. Over the centuries, many rulers followed. By 1040, groups in Senegal became Muslims. From them Islam spread to the region of today’s Senegal, west Mali, and Guinea. After the Soninke of the Kingdom of Ghana became Muslims about 1076, Islam spread along the Niger River. Muslims established the kingdom of Mali in the thirteenth to fifteenth centuries, and Songhai from1465 to 1600. Farther east, Kanem-Bornu near Lake Chad became Muslim after 1100. In West Africa, like Turkestan, India, and Indonesia, it was traders and later Sufis who introduced Islam, and many rulers accepted it first, followed by others. African Muslim scholars became established in the major towns like Timbuktu, and they taught, wrote and practiced Islamic law as judges. By 1500, Islam was established in West Africa throughout the Sahel belt and along the Niger River into today’s Nigeria.

In East Africa, traders had spread Islam down the coast by the tenth century, and it gradually developed further in the following centuries. In the Sudan, south of Egypt, the population of Nubia gradually became Muslim during the fourteenth century, through immigration of Muslim Arab tribesmen and preaching Islam, and because Christian rule became weak in the region. Muslim rule and influence, however, did not extend south of Khartoum, where the Blue and White Niles before 1500 CE.

Strong Governments and the Spread of Islam. By understanding that the expansion of Muslim rule was different from the spread of Islam among populations, we can see an interesting trend. Ironically, Islam has spread most widely and rapidly among the population at times when Muslim rule was weaker and less unified. When Muslim political regimes were weak, decentralized, disunited, or completely absent, Islam as a religion flourished and often spread to non-Muslims. Influence by traders, Sufis and influence of Muslim culture in the cities aided the spread of Islam to new areas. On the other hand, strong states like the Ottoman Empire in the Balkans during the fifteenth century, or the Sultanate of Delhi and the Mogul empire in northern India, had little success in spreading Islam, though they did gain territory. Non-Muslim populations seem to have viewed these powerful Muslim rulers negatively, and so they resisted conversion to Islam. Whoever did embrace Islam in such circumstances, if not for material gain, usually did so because of the efforts of merchants, teachers and traveling Sufi preachers, who were not part of the government. Although the conversion of rulers has often influenced other people in a society to accept Islam, these conversions were not the result of conquests. As in West Africa, East Africa and Southeast Asia, they were far from the ruling centers, but came to know about Islam through the example and teaching of traders and travelers who came in their wake.


Khalid Blankinship, "The Spread of Islam," in World Eras: Rise and Spread of Islam, 622-1500, S. L. Douglass, ed. (Farmington, MI: Gale, 2002), pp. 230-232.

Richard Bulliet, Conversion to Islam in the Medieval Period: An Essay in Quantitative History (Cambridge, Mass: Harvard University Press, 1979).

Bulliet, Islam: the View from the Edge (New York: Columbia University Press, 1994)