Trade relations between Arabia and the Sub-continent dated back to ancient times. Long before the advent of Islam in Arabia, the Arabs used to visit the coast of Southern India, which then provided the link between the ports of South and South East Asia. After the Arab traders became Muslim, they brought Islam to South Asia. Several local Indians living in the coastal areas embraced Islam. However, it was the Muslim conquests in Persia, including the provinces of Kirman and Makran, which brought the Arabs face to face with the then ruler of Sindh, who had allied with the ruler of Makran against the Muslims. But, it was not until the sea borne trade of the Arabs in the Indian Ocean was jeopardized that serious attempts were made to subjugate Sindh.
During the reign of the great Umayyad Caliph Walid bin Abdul Malik, Hajjaj bin Yousaf was appointed as the governor of the Eastern Provinces. At that time, Raja Dahir, a Brahman, ruled Sindh. However, the majority of the people living in the region were Shudders or Buddhists. Dahir treated members of these denominations inhumanly. They were not allowed to ride horses or to wear a turban or shoes. Sindhi pirates, protected by Dahir, were active on the coastal areas and whenever they got a chance, they plundered the ships passing by Daibul.
In 712, Hajjaj sent 6,000 select Syrian and Iraqi soldiers, a camel corps of equal strength and a baggage train of 3,000 camels to Sindh under the command of his nephew and son in-law, Imad-ud-din Muhammad bin Qasim, a young boy of just seventeen years. He also had a ‘manjaniq’, or catapult, which was operated by 500 men and could throw large stones a great distance. On his way the governor of Makran, who provided him with additional forces, joined him. Also, a good number of Jats and Meds, who had suffered at the hands of native rulers, joined the Arab forces.
Muhammad bin Qasim first captured Daibul. He then turned towards Nirun, near modern Hyderabad, where he easily overwhelmed the inhabitants. Dahir decided to oppose the Arabs at Raor. After a fierce struggle, Dahir was overpowered and killed. Raor fell into the hands of the Muslims. The Arab forces then occupied Alor and proceeded towards Multan. Along the way, the Sikka (Uch) fortress, situated on the bank of the Ravi, was also occupied. The Hindu ruler of Multan offered resistance for two months after which the Hindus were overpowered and defeated. Prior to this, Muhammad bin Qasim had taken Brahmanabad and a few other important towns of Sindh. Muhammad bin Qasim was planning to proceed forward when the new Caliph Suleman bin Abdul Malik recalled him. After the departure of Muhammad bin Qasim, different Muslim generals declared their independence at different areas.
The Muslim conquest of Sindh brought peace and prosperity to the region. Law and order was restored. The sea pirates of Sindh, who were protected by Raja Dahir, were crushed. As a result of this, sea trade flourished. The port of Daibul became a very busy and prosperous commercial center. When Muhammad bin Qasim conquered Sindh, the local people, who had been living a life of misery, breathed a sigh of relief. Qasim followed a lenient policy and treated the local population generously. Everyone had full religious freedom and even the spiritual leaders of local religions were given salaries from the government fund. No changes were made in the local administration and local people were allowed to hold offices – particularly in the revenue department. All taxes were abolished and Jaziah جزية was imposed. Everyone was treated equally. Poor people, especially Buddhists, were very impressed by his policies and many of them embraced Islam. Several Mosques and madrasas were constructed in important towns. In a short period of time Sindh became a center of Islamic learning. A number of religious scholars, writers and poets emerged and they spread their knowledge. The Muslims learned Indian sciences like medicine, astronomy and mathematics. Sanskrit books on various subjects were translated into Arabic. During the reign of Haroon al Rasheed, a number of Hindu scholars were even invited to Baghdad.
The establishment of Muslim rule also paved way for future propagation of Islam in Sindh and the adjoining regions. Later Sindh also attracted Ismaili missionaries who were so successful that Sindh passed under Ismaili rule. With the conquest of Lahore by Mahmud of Ghazni, missionary activity began again under the aegis of Sufis who were the main agents in the Islamization of the entire region.
The opening of Central Asia and the implementation of Islam was completed in the eighth century A.D., and brought to the region a new belief and culture that until now continues to be dominant. The Muslims first entered Mawarannahr in the middle of the seventh century through raids during their conquest of Persia. The Soghdians and other Iranian peoples of Central Asia were unable to defend their land against the Khilafah because of internal divisions and the lack of strong indigenous leadership. The Muslims, on the other hand, were led by a brilliant general, Qutaybah ibn Muslim, and were highly motivated by the desire to spread the Islamic religion. Because of these factors, and the strength of the Islamic ‘aqeedah and the nature of the shari’a, the population of Mawarannahr was easily liberated.
The new way of life brought by the Muslims spread throughout the region. The native cultures were replaced in the ensuing centuries as Islam molded the people into a single ummah أمة - the Islamic ummah. However, the destiny of Central Asia as an Islamic region was firmly established by the Khilafah's (Caliph Abu'l-Abbas) victory over the Chinese armies in 750 in a battle at the Talas River. Under Islamic rule, Central Asia was an important centre of culture and trade for centuries. The language of government, literature, and commerce, originally Persian became Arabic (however as the Abbasid Caliphate began to weaken and Arabic became neglected, the Persian language began to regain its pre-eminent role in the region as the language of literature and government). Mawarannahr continued to be an important political player in regional affairs. During the height of the Abbasid Caliphate in the eighth and the ninth centuries, Central Asia and Mawarannahr experienced a truly golden age. Bukhara became one of the leading centers of learning, culture, and art in the Muslim world, its magnificence rivaling contemporaneous cultural centers such as Baghdad, Cairo, and Cordoba. Some of the greatest historians, scientists, and geographers in the history of Islamic culture were natives of the region, and one of the copies of the Quran originally prepared in the time of Caliph Uthman is kept in Tashkent.
The new Islamic spiritual and political situation in Central Asia determined a new technological and cultural progress. It marked the production of the Samarkand paper (since the 8th century under the Chinese influence the people of Samarkand learned to manufacture paper from the rags), which supplanted papyrus and parchment in the Islamic countries at the end of the 10th century. Furthermore, scientists who were citizens of the Khilafah such as al-Khawarezmi, Beiruni, Farabi, Abu Ali ibn Sina (Avicenna) brought fame to the area all over the world, generating respect across the world, and many scientific achievements of the epoch made a great impact on the European science (it is enough to mention the astronomical tables of Samarkand astronomers from Ulughbek's observatory.) During the comparatively peaceful era of Islamic rule, culture and the arts flourished in Central Asia. Jizya جزية was imposed upon all who refused to accept Islam and the Jewish historian Benjamin of Tudela noted during his travels in 1170 the existence of a Jewish community numbering 50,000 in nearby Samarkand.
The actual timing and introduction of the Islamic religion and its practice to Southeast Asia is subject to debate. European historians have argued that it came through trading contacts with India whereas some Southeast Asian Muslim scholars claim it was brought to the region directly from Arabia in the Middle East. Other scholars claim that Muslim Chinese who were engaged in trade introduced it.
Whatever the source, scholars acknowledge that Muslim influence in Southeast Asia is at least six centuries old, or was present by 1400 A.D. Some argue for origins to at least 1100 A.D. in the earliest areas of Islamic influence, such as in Aceh, northern Sumatra in Indonesia.