The Spread of Islam in Africa & Asia

In 711 CE, a Muslim army crossed the Strait of Gibraltar and entered the Iberian Peninsula. Within a decade, it controlled most of what is now Spain and Portugal. In the same century, other Muslim forces pushed east past the Oxus River into Central Asia, and south along the Indian Ocean coast as far as the Malabar. By 750, Islam had spread from the Atlantic to the borders of China in under 120 years.

That early expansion was, in part, military. But armies explain almost none of what happened next.

The caliphates eventually stopped growing. The armies returned to their garrisons or dissolved into local populations. Yet Islam kept moving — into the forests of West Africa, across the monsoon routes to the islands of Southeast Asia, down the Swahili coast of East Africa to Mozambique and beyond. No caliph ordered these conversions. No army enforced them. What moved was something harder to quantify: a set of practices, texts, legal frameworks, and spiritual disciplines that proved adaptable enough to take root in almost any soil.