How did Islam become widespread in Eritrea’s lowlands and coastal areas?

The spread of Islam in Eritrea’s lowlands and coastal areas was primarily driven by the expansion of Muslim power from Arabia following the rise of the faith in the 7th century CE. As this influence flowed across the Red Sea coast, it displaced existing creeds in the lowlands of the Horn of Africa and forced Christian populations to retreat into the mountainous interior.1

This historical shift established Islam as the predominant faith among the pastoralist populations inhabiting the eastern coast and the western plains of Eritrea. Over time, the region’s strategic location along the coast facilitated ongoing commercial and cultural exchanges with the Middle East, further cementing the presence of Islam in these areas. Today, this religious distribution remains a significant aspect of Eritrean society, with Islam and Christianity continuing to shape the country's cultural and political landscape.12