Migration and Urbanization on the Swahili Coast

Photo credit: Ryan Raaum

Dr. Ryan Raaum (Lehman College / CUNY) describes his ongoing NSF-funded project reconstructing the human population history of the East African coast. This interdisciplinary project brings together specialists in archaeology, skeletal biology, population genetics, and ancient DNA in order to unravel the establishment and transformation of human populations on the Swahili Coast.

Photo credit: Ryan Raaum

The Swahili Coast runs from Somalia to Mozambique, with the densest concentrations of known settlements on the coasts of modern day Kenya and Tanzania. Unlike their neighbors, the Swahili people of the East African coast are predominantly Muslim, wrote their language in the Arabic script prior to European colonization, and have constructed stone towns since the end of the first millennium CE. Until the 1970s, both foreign and local commentators generally viewed all "civilized" features of the region as introduced by trade and intermarriage with Arabs and Persians. In fact, the coastal culture and people were not considered African, but rather were assumed to descend from Near Eastern trading settlements. Swahili oral and written histories do little to dispel this notion of external influence, with traditions tracing family lineages to foreign ancestors.

Since the 1980s, postcolonial archaeologists, linguists, and historians have shown that there is little evidence for these colonial scenarios of an Arab source for urbanization on the coast. Archaeological excavations have shown that the material culture of the region does not undergo any dramatic change from the pre-urban period to the urban period (roughly pre- to post-1000 CE). Mosques are introduced during this time and some settlements transition from non-stone to stone architecture, but the artifacts of day-to-day life do not change. Residents of pre-stone settlements and stone towns use the same pottery and other implements, have the same diets, and construct buildings and settlements on the same plan. This continuity is not consistent with the colonial idea that the stone towns were Arabian settlements. Linguistic analysis has also shown that the extensive Arabic vocabulary in the Swahili language is a later superficial addition to a fundamentally African language in the Bantu group of languages.

Much of the Arabian influence on the coast can be traced to the 1700s, when Omani Arabs took political control of the region. The region was so important to the Omanis that from 1840-1861 the capital of the Sultanate of Oman was moved from Muscat to the island of Zanzibar off the coast of Tanzania (and subsequently split into separate Sultanates of Oman and Zanzibar). The period of Omani dominance initiated an Arabization of the local population, in which many Arabic words were assimilated into the Swahili language, local high-status families sought inter-marriage with politically dominant Omani families, and family lineage origins were re-discovered in Middle Eastern ports such as Shiraz in Iran. This Arabophilic milieu contributed to early investigators' conclusions that Arabs, Persians, and Israelites – and not Africans themselves - founded many of the preindustrial cities found in sub-Saharan Africa.

While our current understanding of the history of the region places indigenous populations at the center of developments, there are clear indications – both archeological and historic – of early foreign interactions, especially with Southwest Asia. The antiquity and volume of trade and exchange in the Indian Ocean Trading and Persian Gulf trading systems is beyond doubt. These trading complexes have linked East, South East, South and South West Asia to East, South and North Africa and the Mediterranean since at least 1000 BCE, and even into the Bronze Age (ca. 3500 – 1500 CE). Certainly the antiquity of African domesticates in Asia and Asian domesticates in Africa and distribution of trade goods in Africa, Southwest and South Asia attest to this interaction as far back as 2000 BCE if not before. And while the archaeological evidence does not support the idea of any predominantly Arab settlements in the region prior to the 1700s, the first definitive mosque on the coast is dated to the 800s at the site of Shanga in the Lamu Archipelago and the Arabic script is adopted for written Swahili by the 1200s.

My colleagues and I have received NSF funding to examine the role of migration (both regional and foreign) in the development of these large autonomous Swahili towns and city-states that grew out of small fishing, agrarian, and pastoral settlements on the East African coast in the late first millennium CE. I will be examining the distribution of maternal (mtDNA) and paternal (Y chromosome) lineages in an extensive collection of DNA samples from the contemporary Swahili-speaking inhabitants of the coast. Our sampling strategy for these contemporary collections includes the Swahili residents of stone towns, of satellite communities to the stone towns, and smaller settlements throughout the Kenyan coastal region. Dr. Chapurukha Kusimba (The Field Museum, Chicago) will be conducting archaeological excavations at the site of Mtwapa. Dr. Janet Monge (University of Pennsylvania) will study the skeletal remains from Dr. Kusimba’s excavations. Dr. Sloan Williams (University of Illinois-Chicago) will extract and analyze ancient DNA from skeletal remains from Dr. Kusimba’s excavations and museum collections. These skeletal and genetic examinations of archaeological remains, which are direct analyses of the past populations of the coast, will be integrated with the genetic evidence from living populations to reconstruct the recent human population history of the coast.