The Swahili people of East Africa are of mixed African and Persian descent going back a thousand years, according to a study of DNA that seeks to settle a vexed century-old debate.
The findings of the first genetic analysis of Swahili skeletal remains align with Swahili oral traditions of Persian heritage. They contradict a modern scholarly view that there was little contribution from foreigners to the Swahili civilisation.
However, they also refute the diametrically opposed position — prevalent in colonial times — that Africans had little input in the Swahili’s achievements.
Stephanie Wynne-Jones, Professor of African Archaeology at the University of York and co-author of the study in the journal Nature, said: “This data must be seen as a catalyst for a new, less binary, approach to Swahili society. It shows that people were moving and establishing deep connections and families in the Indian Ocean region, and that Persian migrants would have been part of the cosmopolitan world created by coastal African societies.”
The Swahili were among the first Muslims in Sub-Saharan Africa and controlled Indian Ocean trade routes from their wealthy city-states such as Mombasa and Zanzibar. During the medieval and early modern periods they traded goods such as glass beads, cloth and ceramics into Africa and exported raw materials including gold, ivory and wood, as well as slaves.
In the 14th-century, the Moroccan traveller Ibn Battuta described the Swahili-coast city of Kilwa as “among the most beautiful of cities and elegantly built.”
Swahili claims of Persian roots were noted by European colonisers as early as the 16th century when the Portuguese translated a chronicle saying Swahili cities were founded by merchant princes from Shiraz. Later racist imperialists emphasised the alleged non-African origins of the Swahili to explain their remarkable successes.
More recently, some other Africans have accused Swahilis of falsely claiming Asian heritage to play down their Africanness and obtain social status.
Wynne-Jones said: “The question of Persian origins is the big question of Swahili studies but a really vexed one. There has been a very deep and detailed set of studies over the last 20-30 years showing the indigenous roots of Swahili society through archaeology and linguistics and history, and really working to think about the Swahili as an African society. But there has always been a challenge in that the Swahili themselves tell stories of Persians or Arabs coming to the coast. And we know there was this long history of interacting with people from overseas, and trade not only with the Persian Gulf but with the wider Indian Ocean world and as far as China.”
To address the issue, an international team of geneticists and archaeologists analysed DNA from bones of 80 individuals from the Swahili coast and adjacent inland areas dating from 1300-1900, including many late medieval samples.
The analysis, conducted at the Reich Laboratory at Harvard University, indicates that, around 1000AD, migrants from Persia intermingled with Africans at numerous locations along the Swahili coast. The Persian migrants contributed about half of the ancestry of the later individuals whose remains were studied. Most of the migrants were men and most of the Africans involved were women.
The timing coincides with archaeological evidence for a cultural transformation on the Swahili coast, including the widespread adoption of Islam. At Kilwa in modern-day Tanzania, coin evidence has dated a ruler linked to a Shirazi Persian dynasty to the mid-11th century.
Although the sex imbalance identified in the study could reflect forced marriages or rapes, the team said it was more likely to have arisen due to alliances with local trading families. This was supported by the fact that the children of Persian fathers and Swahili-coast mothers passed down their mothers’ language. Moreover, the region’s matriarchal traditions did not change even after locals settled down with people from patriarchal regions in Persia and Arabia.
The study doesn’t only confirm genetic links to the Persian Gulf but also reveals ties farther afield. It indicates that the Persian migrants derived about 10 per cent of their own ancestry from Indian women. The resulting contribution of South Asians to the Swahili gene pool was unanticipated although unsurprising given the regional trade routes.
In later centuries, arrivals of Arabs and people from elsewhere in Africa further altered the genetic makeup of Swahili-coast communities, according to the analysis. Nevertheless, a sample of 93 living Swahili speakers who reported that their ancestors had a Swahili identity for many generations derived 46-77 per cent of their ancestry from the medieval Swahili or similarly mixed groups.
The researchers emphasised that the foundations of the Swahili civilisation were laid long before the arrivals from the Persian Gulf. Wynne-Jones said: “On the Swahili coast we see the first permanent settlements integrated into Indian Ocean trade networks in the 7th century. There was a series of networked settlements along the coast in the late first millennium and they were trading with Madagascar and the Persian Gulf. People sometimes talk about them as the Proto-Swahili and they were populations that became the Swahili.
“However, something happened in the 11th century. Some settlements were abandoned and new sites were founded. There seems to have been a shift in international trade patterns. We know that in the late 10th century there was a big earthquake at Siraf, the large trading port in the Persian Gulf. There was this sort of break on the Swahili coast and then, in the 11th century, we start seeing mosques being built all over the place and tombs being built out of coral and new towns being founded. The moment of DNA admixture lines up with these movements and this new system of trade.”
Today, millions of people in coastal East Africa identify as Swahili and the Swahili language — an African Bantu language with Asian loan words — is spoken by an even larger number of people over a broader area.
Wynne-Jones said the study findings were likely to prove controversial. “To find this Persian ancestry flies in the face of what a lot of people in the region would like to see. We did actually go back to Kilwa and Songo Mnara where our samples came from and talked to them about the results to check they were happy to have them published. And there they were delighted with it, because it fitted with their stories and they effectively said, ‘We told you so’. But there are a lot of different audiences in East Africa and I think that won’t always be the reception.”