The first published reference to Mombasa is in the work of the geographer, al-Idrisi, in the twelfth century (Berg and Walter 1968:51), so the town has existed for at least eight centuries, but there is little agreement on just when it was founded or by whom (Mathew 1963:94–127; Prins 1967:40–42; Salim 1973:9–10). Horton's excavations at Shanga on Pate Island south of Mombasa show that the "Swahili were African [not Arab] in origin" and by the ninth century were becoming Muslim and establishing settlements at numerous sites along the East African coast (Horton 1986, 1987:88–89). Considering both archaeological and linguistic evidence, Nurse and Spear (1985:57–58) conclude that the city "was founded . . . ca. 1000" by Swahili whose ancestors came from the north in Lamu archipelago and the adjacent mainland where the Swahili ethnic group may have originated several centuries earlier.
According to at least one historian of the Mombasa Swahili community,
the city founders were Swahili but not those who are the direct forebears of the contemporary Swahili community (Berg 1968:38–39). In this view, the latter, who are sometimes called Theneshara Taifa, the Twelve Tribes, did not come to live on Mombasa island until three or four centuries ago and were preceded there by two earlier Swahili groups (ibid.).
At first, what is now Mombasa was called Gongwa and was occupied by a Swahili group under Queen Mwana Mkisi (ibid., 42). Her dynasty was followed in about 1500 by a Shirazi dynasty founded by Shehe Mvita whose name thereafter became the Swahili name, Mvita, of the city (Nurse and Spear 1985:73). Early in the sixteenth century, during the reign of this dynasty, the Portuguese made their first visits to Mombasa. They found it to be a stone-built city with twenty to thirty thousand Muslim inhabitants trading with other parts of the East African coast and with ports on the west coast of India (Berg and Walter 1968:51–52). In this and subsequent visits, the Portuguese ships and troops devastated Mombasa three times: in 1505, 1526, and 1589 (Berg 1968:45). Despite this, during the early sixteenth century, Mombasa was described by the chronicler of Indian Ocean trade, Tomé Pires, as "a place of great traffic" in produce of every kind (Freeman-Grenville 1963:152).
The ethnic orgins of all these active early residents of the city are not entirely clear, but, despite the vital and large part played by African sources in much that is Swahili (Nurse and Spear 1985; Horton 1986, 1987:87), there were doubtless cultural and biological contributions from peoples from outside the continent. Thus, although the role of Omani Arabs in the history of the Mombasa Swahili will be seen to be a significant one, it is difficult to establish clearly whether or not immigrants from Oman had already become part of the community before the arrival of the Portuguese, the first Europeans to affect the group directly.
We do know that families and rulers of Omani origin were well established on Pate Island (250 km to the north of Mombasa) and elsewhere on the coast in the fourteenth century (Salim 1973:21). And it is quite likely that there were other influential immigrants from that area present on the coast as early as the seventh century (Prins 1967:40–41).
Arabs from another area, the Hadhramaut, in what is now northern Yemen, arrived on the East African coast during the fourteenth and fifteenth centuries. They profoundly influenced the culture of the Swahili ethnic group, including that of the Mombasa community, in a number of ways, including, especially, religion (Salim 1973:141).
Currently, and for at least several centuries, all members of the Swahili ethnic group are and have been adherents of the Shafi madhahab (canon or sect) of Sunni Islam (Swartz 1978). This faith seems to have been brought to the area no later than the fourteenth century by a large migration of Sharifs (descendants of Prophet Mohammed) from the Hadramaut (Salim 1973:141–142). The same group of immigrants also founded the poetic verse form,
utenzi, characteristic of the Swahili, as well as their method of religious teaching and the according of prestige to the families of Sharifs (ibid.; Harries 1962:86–88).
If, as seems likely, the Hadhrami brought the Shafi canon to Mombasa, they arrived not later than the early fourteenth century, or perhaps the thirteenth, as can be seen from the reports of Ibn Battuta who visited Mombasa in 1329 or 1331. He observed that the people, although living in poverty, had well-constructed wooden mosques and were pious followers of the Shafi canons of the Sunni branch of Islam (Berg and Walter 1968:51).
Whatever the exact dates of arrival of the various Arab immigrants, the active trade noted by Ibn Battuta doubtless contributed to migration into the area. By the fifteenth century, this trade was largely focused on traffic to and from the Red Sea area (Pouwells 1987:38), and Mombasa, with its northern neighbor, Malindi, and, perhaps, Mogadishu, surpassed the once dominant southern town of Kilwa as the main entrepôt to Eastern Africa (ibid.). During this same period, the people of Mombasa, both slaves and their owners, were highly productive farmers in the plantations on the island and adjacent mainland (Cooper 1977:100–102).
Probably because of this economic activity, migration to the island in the sixteenth century continued despite a disastrous military campaign against neighboring Malindi, attacks by marauding groups from the north and south, and a number of political upheavals. Even as political instability grew and rulers came and went at shorter and shorter intervals, the Mombasa Swahili continued to become cosmopolitan at a rate that increased with time (Berg 1968:45–46).