By Published: June 13, 2019

New maps of pre-colonial Africa provide context on the slaves who departed from the Bight of Benin

Those who boarded slave ships from the Bight of Benin, or the Slave Coast of Africa, lost more than their homes—they lost their identities. New maps of a former kingdom made by a University of Colorado Boulder professor, though, may help shed some light on the centuries-old question of where they came from.

These 21 maps, including one that is animated, are the first of their kind to give boundaries to the kingdom of Oyo—which was located in present-day southwestern Nigeria, parts of Benin and Togo—right around the time of the kingdom’s collapse.

Headshot of Lovejoy

Henry Lovejoy, seen here, used Historical GIS to map the collapse
of the Oyo kingdom.

Rather than serve as a definitive source, the hope is that these maps, published this week in the Journal of Global Slavery, along with data analysis by CU Boulder’s Laboratory of Interdisciplinary Statistical Analysis or LISA, will provide a degree of clarity for this turbulent time during the Atlantic Slave trade.

“I think having visualization really clarifies a lot of things. It’s clarified a lot of my own research, so I can only imagine how it can clarify this particular period in history in a place that had a huge impact on the America’s that people just don’t get because there aren’t maps,” said Henry Lovejoy, the study’s author and an assistant professor of history at CU Boulder.

At its peak, the Yoruba kingdom of Oyo was one of the largest and most influential West African states. It was established in roughly the 13th century, and is best known for its cavalries that would patrol the forested savannas. The kingdom had a dark side, though, that made it infamous and ultimately led in part to its demise: its role in the African slave trade.

The kingdom of Oyo began simply as the city of Oyo, and while it steadily grew on its own, the slave trade out of the Bight of Benin brought it wealth and prosperity, leading to even greater conquests of nearby peoples. During this period, an estimated 128,000 people were captured by these cavalries during these conflicts, enslaved and sent to the Americas—particularly Brazil and Cuba.

But the question remained: from where?

Present-day maps cannot be applied to pre-colonial Africa, and what other maps do exist are inconsistent or fragmented at best. Lovejoy decided to fix that through a Historical GIS (Geographic Information Systems) experiment.

He obtained geographic and historic data from established primary and secondary sources, like the Trans-Atlantic Slave Trade Database, and then imported that data into Quantum GIS, which is an open source version of the popular mapping software. He then used a plug-in to plot the creation and disappearances of towns surrounding and within Oyo when it was at its largest and to show the coming and goings of slave ships.

Using these techniques, Lovejoy was able to show the general uncertainty surrounding Africa’s internal geography at this time, including the approximate ebb and flow of Africa’s pre-colonial boundaries and the general human migrations at play due to the slave trade.


But using GIS this way doesn’t come without some controversy.

“There’s so much data that’s missing, especially if you want to get down into the level of grains of sand or erosion,” acknowledged Lovejoy. “So, it’s really becoming its own sort of class of scholarship, I think, to look at the world in terms of these places that don’t have a lot of information, but have very rich histories.”

Lovejoy just cautions that these maps should be used only as approximations and not the end-all-be-all of maps for the Oyo kingdom. But it’s a start.

Lovejoy plans to work with LISA to use these maps and the conflict data to start creating mathematical formulas and heat maps to estimate where people may have originated from. By doing this, he hopes to provide a better history and understanding of not just this region of West Africa, but also of the America’s.

“I’m just working on this small quadrant of Africa, but we’re dealing with 12 and a half million people. This is only 75,000,” said Lovejoy. “We’re getting all of these things in place; then it will be possible to sort of pull more people into the project, but I think people need to visualize it first, before they can understand what’s starting to happen.”