The spread of Islam began shortly after the Prophet Muhammad's death in 632. By that time, he and his followers had converted most of Arabia's tribes and towns to Islam (literally, submission), which Muslims maintained united the individual believer, the state, and society under God's will. Islamic rulers, therefore, exercised temporal and religious authority. Islamic law , which was derived primarily from the Quran, encompassed all aspects of the lives of believers, who were called Muslims ("those who submit" to God's will).

Within a generation of Muhammad's death, Arab armies had carried Islam north and east from Arabia into North Africa. Muslims imposed political control over conquered territories in the name of the caliph (the Prophet's successor as supreme earthly leader of Islam). The Islamic armies won their first North African victory in 643 in Tripoli (in modern Libya). However, the Muslim subjugation of all of North Africa took about seventy-five years. The Arabs invaded Nubia in 642 and again in 652, when they laid siege to the city of Dunqulah and destroyed its cathedral. The Nubians put up a stout defense, however, causing the Arabs to accept an armistice and withdraw their forces.

The Arabs

Contacts between Nubians and Arabs long predated the coming of Islam, but the arabization of the Nile Valley was a gradual process that occurred over a period of nearly 1,000 years. Arab nomads continually wandered into the region in search of fresh pasturage, and Arab seafarers and merchants traded in Red Sea ports for spices and slaves. Intermarriage and assimilation also facilitated arabization. After the initial attempts at military conquest failed, the Arab commander in Egypt, Abd Allah ibn Saad, concluded the first in a series of regularly renewed treaties with the Nubians that, with only wity arrangements whereby both parties agreed that neither would come to the defense of the other in the event of an attack by a third party. The treaty obliged both to exchange annual tribute as a goodwill symbol, the Nubians in slaves and the Arabs in grain. This formality was only a token of the trade that developed between the two, not only in these commodities but also in horses and manufactured goods brought to Nubia by the Arabs and in ivory, gold, gems, gum arabic, and cattle carried back by them to Egypt or shipped to Arabia.

Acceptance of the treaty did not indicate Nubian submission to the Arabs, but the treaty did impose conditions for Arab friendship that eventually permitted Arabs to achieve a privileged position in Nubia. For example, provisions of the treaty allowed Arabs to buy land from Nubians south of the frontier at Aswan. Arab merchants established markets in Nubian towns to facilitate the exchange of grain and slaves. Arab engineers supervised the operation of mines east of the Nile in which they used slave labor to extract gold and emeralds. Muslim pilgrims en route to Mecca traveled across the Red Sea on ferries from Aydhab and Sawakin, ports that also received cargoes bound from India to Egypt.

Traditional genealogies trace the ancestry of most of the Nile Valley's mixed population to Arab tribes that migrated into the region during this period. Even many non-Arabic-speaking groups claim descent from Arab forebears. The two most important Arabic-speaking groups to emerge in Nubia were the Jaali and the Juhayna . Both showed physical continuity with the indigenous pre-Islamic population. The former claimed descent from the Quraysh, the Prophet Muhammad's tribe. Historically, the Jaali have been sedentary farmers and herders or townspeople settled along the Nile and in Al Jazirah. The nomadic Juhayna comprised a family of tribes that included the Kababish, Baqqara, and Shukriya. They were descended from Arabs who migrated after the thirteenth century into an area that extended from the savanna and semidesert west of the Nile to the Abyssinian foothills east of the Blue Nile. Both groups formed a series of tribal shaykhdoms that succeeded the crumbling Christian Nubian kingdoms and that were in frequent conflict with one another and with neighboring non-Arabs. In some instances, as among the Beja, the indigenous people absorbed Arab migrants who settled among them. Beja ruling families later derived their legitimacy from their claims of Arab ancestry.

Although not all Muslims in the region were Arabic-speaking, acceptance of Islam facilitated the arabizing process. There was no policy of proselytism, however, and forced conversion was rare. Islam penetrated the area over a long period of time through intermarriage and contacts with Arab merchants and settlers. Exemption from taxation in regions under Muslim rule also proved a powerful incentive to conversion.
 

The Decline of Christian Nubia

Until the thirteenth century, the Nubian kingdoms proved their resilience in maintaining political independence and their commitment to Christianity. In the early eighth century and again in the tenth century, Nubian kings led armies into Egypt to force the release of the imprisoned Coptic patriarch and to relieve fellow Christians suffering persecution under Muslim rulers. In 1276, however, the Mamluks (Arabic for "owned"), who were an elite but frequently disorderly caste of soldier-administrators composed largely of Turkish, Kurdish, and Circassian slaves, intervened in a dynastic dispute, ousted Dunqulah's reigning monarch and delivered the crown and silver cross that symbolized Nubian kingship to a rival claimant . Thereafter, Dunqulah became a satellite of Egypt.

Because of the frequent intermarriage between Nubian nobles and the kinswomen of Arab shaykhs, the lineages of the two elites merged and the Muslim heirs took their places in the royal line of succession. In 1315 a Muslim prince of Nubian royal blood ascended the throne of Dunqulah as king. The expansion of Islam coincided with the decline of the Nubian Christian church. A "dark age" enveloped Nubia in the fifteenth century during which political authority fragmented and slave raiding intensified. Communities in the river valley and savanna, fearful for their safety, formed tribal organizations and adopted Arab protectors. Muslims probably did not constitute a majority in the old Nubian areas until the fifteenth or sixteenth century.
 

The Rule of the Kashif

For several centuries Arab caliphs had governed Egypt through the Mamluks. In the thirteenth century, the Mamluks seized control of the state and created a sultanate that ruled Egypt until the early sixteenth century. Although they repeatedly launched military expeditions that weakened Dunqulah, the Mamluks did not directly rule Nubia. In 1517 the Turks conquered Egypt and incorporated the country into the Ottoman Empire as a pashalik (province).

Ottoman forces pursued fleeing Mamluks into Nubia, which had been claimed as a dependency of the Egyptian pashalik. Although they established administrative structures in ports on the Red Sea coast, the Ottomans exerted little authority over the interior. Instead, the Ottomans relied on military kashif (leaders), who controlled their virtually autonomous fiefs as agents of the pasha in Cairo, to rule the interior. The rule of the kashif, many of whom were Mamluks who had made their peace with the Ottomans, lasted 300 years. Concerned with little more than tax collecting and slave trading, the military leaders terrorized the population and constantly fought among themselves for title to territory.
 

The Funj

At the same time that the Ottomans brought northern Nubia into their orbit, a new power, the Funj, had risen in southern Nubia and had supplanted the remnants of the old Christian kingdom of Alwa. In 1504 a Funj leader, Amara Dunqas, founded the Black Sultanate (As Saltana az Zarqa) at Sannar. The Black Sultanate eventually became the keystone of the Funj Empire. By the mid-sixteenth century, Sannar controlled Al Jazirah and commanded the allegiance of vassal states and tribal districts north to the third cataract and south to the rainforests.

The Funj state included a loose confederation of sultanates and dependent tribal chieftaincies drawn together under the suzerainty of Sannar's mek (sultan). As overlord, the mek received tribute, levied taxes, and called on his vassals to supply troops in time of war. Vassal states in turn relied on the mek to settle local disorders and to resolve internal disputes. The Funj stabilized the region and interposed a military bloc between the Arabs in the north, the Abyssinians in the east, and the non-Muslim blacks in the south.

The sultanate's economy depended on the role played by the Funj in the slave trade. Farming and herding also thrived in Al Jazirah and in the southern rainforests. Sannar apportioned tributary areas into tribal homelands (each one termed a dar; pl., dur), where the mek granted the local population the right to use arable land. The diverse groups that inhabitated each dar eventually regarded themselves as units of tribes. Movement from one dar to another entailed a change in tribal identification. (Tribal distinctions in these areas in modern Sudan can be traced to this period.) The mek appointed a chieftain (nazir; pl., nawazir) to govern each dar. Nawazir administered dur according to customary law, paid tribute to the mek, and collected taxes. The mek also derived income from crown lands set aside for his use in each dar.

At the peak of its power in the mid-seventeenth century, Sannar repulsed the northward advance of the Nilotic Shilluk people up the White Nile and compelled many of them to submit to Funj authority. After this victory, the mek Badi II Abu Duqn (1642-81) sought to centralize the government of the confederacy at Sannar. To implement this policy, Badi introduced a standing army of slave soldiers that would free Sannar from dependence on vassal sultans for military assistance and would provide the mek with the means to enforce his will. The move alienated the dynasty from the Funj warrior aristocracy, which in 1718 deposed the reigning mek and placed one of their own ranks on the throne of Sannar. The mid-eighteenth century witnessed another brief period of expansion when the Funj turned back an Abyssinian invasion, defeated the Fur, and took control of much of Kurdufan. But civil war and the demands of defending the sultanate had overextended the warrior society's resources and sapped its strength.

Another reason for Sannar's decline may have been the growing influence of its hereditary viziers (chancellors), chiefs of a non-Funj tributary tribe who managed court affairs. In 1761 the vizier Muhammad Abu al Kaylak, who had led the Funj army in wars, carried out a palace coup, relegating the sultan to a figurehead role. Sannar's hold over its vassals diminished, and by the early nineteenth century more remote areas ceased to recognize even the nominal authority of the mek.
 

The Fur

Darfur was the Fur homeland. Renowned as cavalrymen, Fur clans frequently allied with or opposed their kin, the Kanuri of Borno, in modern Nigeria. After a period of disorder in the sixteenth century, during which the region was briefly subject to Bornu, the leader of the Keira clan, Sulayman Solong (1596-1637), supplanted a rival clan and became Darfur's first sultan. Sulayman Solong decreed Islam to be the sultanate's official religion. However, large-scale religious conversions did not occur until the reign of Ahmad Bakr (1682-1722), who imported teachers, built mosques, and compelled his subjects to become Muslims. In the eighteenth century, several sultans consolidated the dynasty's hold on Darfur, established a capital at Al Fashir, and contested the Funj for control of Kurdufan.

The sultans operated the slave trade as a monopoly. They levied taxes on traders and export duties on slaves sent to Egypt, and took a share of the slaves brought into Darfur. Some household slaves advanced to prominent positions in the courts of sultans, and the power exercised by these slaves provoked a violent reaction among the traditional class of Fur officeholders in the late eighteenth century. The rivalry between the slave and traditional elites caused recurrent unrest throughout the next century.