  Intra-African conflicts during the collapse of the kingdom of Oyo from 1817
to 1836 resulted in the enslavement of an estimated 121,000 people who were
then transported to coastal ports via complex trade networks and loaded onto
slave ships destined for the Americas. Historians have a good record of where
these people went across the Atlantic, but little is known about where
individuals were from or enslaved \textit{within} Africa. In this work, we
develop a novel two-step statistical approach to describe the enslavement of
people given documented violent conflict, the transport of enslaved peoples
from their location of capture to their port of departure, and---given an
enslaved individual's location of departure---that person's probability of
origin. We combine spatial prediction of conflict density via Kriging with a
Markov decision process characterising intra-African transportation. The
results of this model can be visualised using an interactive web application,
plotting estimated conditional probabilities of historical migrations during
the African diaspora. These results help trace the uncertain origins of people
enslaved in this region of Africa during this time period: using the two-step
statistical methodology developed here provides a probabilistic answer to this
question.
