Written accounts tell the story of the Zanj rebellion – a slave revolt that took place in the late 9th century in southern Iraq. Some of the rebels were enslaved Africans working in various sectors of the local economy. Here Honorary Fellow in Archaeology, Peter Brown sheds new light on the timelines.
Thousands of ridges and canals still stand today across a floodplain in southern Iraq. They’ve long been believed to be the remains of a massive agricultural system built by these enslaved people. Creating them, and farming here, could have been what drove the rebellion that’s often thought to have led to the rapid decline of the historic city of Basra and the local economy.
For the first time, our archaeological study offers a firmer timeline for when farming occurred across this landscape. This also allows an insight into how the Zanj rebellion affected the region.
We dated four of the 7,000 abandoned ridge features which cover a large swathe of the Shatt al-Arab floodplain, attesting to a period of agricultural expansion.
Our study finds that this agricultural system was in use for far longer than was previously assumed, calling into question the impact of the rebellion on farming and the local economy.
Our findings enhance our knowledge of the landscape history of southern Iraq and draw attention to the historical significance of landscape features which have often been overlooked.
Abandoned and eroding earthworks litter the floodplain of the Shatt al-Arab – the river forming at the confluence of the Tigris and Euphrates. This flows through southern Iraq out into the Gulf and the Indian Ocean.
Most noticeably, groups of massive, raised, linear ridge features, some of which extend for over a kilometre, are arranged in regular formations. Among these features, the remains of dried-up canals and smaller, adjoining, secondary water channels can be traced.
Today, agriculture in the floodplain is restricted to the band roughly within 5km of the river. But the abandoned features relate to farming in the past across a much larger area. While we don’t know exactly what was grown, cereals like barley or wheat, dates or sugarcane are the most likely crops.
Accounts from travellers who visited the area, as well as historical maps, indicate that the modern agricultural pattern has existed, essentially unchanged, at least since the 17th century. So, the features we see in the landscape today must have been constructed, in use, and abandoned in an earlier period.
New scientific evidence for the dating of these features helps us to understand when this occurred and the historical circumstances around this phase of agricultural expansion.
In 2022, we excavated small trenches into the top of four of the ridges. This allowed us to extract soil samples from their cores. Using a method called optically stimulated luminescence dating, individual grains of soil could be analysed. This allows the length of time since these grains were exposed to sunlight to be calculated. As our samples came from inside the ridge features, where they would have been permanently hidden from the sun, these samples should give the date when the soil was originally deposited.
Until now, no significant fieldwork had been carried out to investigate these features. However, these traces of pre-modern farming have often been linked with one particular historical episode – but without concrete evidence. Documents from the early Islamic period (from about the mid 7th to mid 13th century) provide a detailed account of a slave revolt in southern Iraq during the late 9th century, between 869 and 883.
The Zanj Rebellion saw large groups of slaves rebel against the forces of the Abbasid Caliphate – which ruled most of the Islamic world. The rebellion included violent episodes, including the sacking of the nearby city of Basra and clashes with the forces of the caliph sent to suppress the revolt. This threw southern Iraq into turmoil.
The identity of the Zanj people involved in the uprising has been a focus for debate. “Zanj” is an Arabic term used throughout the medieval period to refer to the Swahili coast of east Africa, though it was also used to refer to Africa more generally. As a result, the Zanj have typically been regarded collectively as enslaved people transported to southern Iraq from east Africa.
While the evidence for slaving traffic between Africa and Iraq during the early Islamic period is uncontroversial, the scale of the trade has been questioned. Based on genetic evidence, and the logistics of shipping large numbers to the Gulf, it has been argued that the majority of African slaves at the time of the revolt came from west and western central Africa via Saharan trade routes, rather than coastal east Africa. Importantly, the people involved in the revolt were not all African slaves – some seem to have been local farmers – so the rebels were a mixed group.
We know little about what the group known as the Zanj were doing before the 869 revolt. Their presence in Iraq is documented for centuries beforehand – smaller scale rebellions occurred in the late 7th century but only a few details are available about the lives of the slaves before the 9th century rebellion.
Some were involved in tasks like transporting flour. Others were dispersed in groups of 50-500 in work camps across the floodplain. Details relating to life within these camps are unavailable yet the written sources suggest the slaves were treated poorly by the “agents” who oversaw them. Other than for agriculture, it’s difficult to explain why such camps would have existed across this zone.
What we know about the Zanj fits closely with the scale of the landscape features visible today. Large numbers of labourers would have been needed, both to transport the soil forming the raised ridges and to farm the areas in between. This must have been enormously difficult work.
It’s often been assumed that the Zanj rebellion caused a significant decline in the region’s economy, including activities like farming. Our results, however, indicate that the earthworks date to the period after the rebellion.
While some samples date to the period immediately after the rebellion, others gave dates from a century or two later, in the 11th, 12th or 13th centuries. Rather than features created in one go, these traces in the landscape were likely added to over a longer period – perhaps as part of the annual farming cycle.
This means the samples we dated likely do not relate to the earliest farming activity but provide a “snapshot” of ongoing work. Since some of the features date to shortly after the rebellion, the slaves discussed in the written sources were likely involved in creating these ridge features. However, farming across this landscape certainly continued for a significant period after the revolt’s conclusion.
Be it climatic change, the impact of a pandemic, or wider economic and political shifts, exactly why such a large area of farmland was later abandoned remains an unanswered question. One which requires further research to answer.
But, by more definitively linking these landscape features to their historical context, we are one step closer to understanding social and economic processes in southern Iraq during the medieval period.
Archaeology adds another dimension to what we know about a historical event like the Zanj rebellion.
Image caption: In southern Iraq, a massive agricultural system was likely built by enslaved Africans who ended up staging a revolt. Courtesy the authors/Cambridge University Press
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