Slave trade and the spread of Islam in Africa

Abstract

We investigate an often overlooked legacy of the Atlantic slave trade: its role in the spread of Islam in West Africa. Building on the historical literature, we examine whether the protection offered by Islamic rulers against enslavement served as an incentive for conversion to Islam. Using a theoretical model, we analyse individuals’ motivations to embrace Islam in response to the threat of slavery. The empirical analysis reveals a negative relationship be- tween the intensity of the Atlantic slave trade and Islamic prevalence, showing that Muslim regions exported fewer slaves. Additionally, areas under Islamic rule, where individuals had de facto protection from enslavement, saw higher conversion rates. These findings are consistent across both historical data on Islamic prevalence after the end of the slave trade (in the early 20th century) and contemporary survey data on religious affiliation. Our results highlight how the Atlantic slave trade not only shaped Africa’s socio-economic development but also significantly influenced the religious landscape, with lasting effects on Islam’s diffusion.