How did Islam spread beyond Arabia after Muhammad’s death?

Following the death of the Prophet Muhammad in 632 CE, the expansion of Islam beyond the Arabian Peninsula was driven by a combination of religious zeal, the desire for new lands and resources, and the strategic exploitation of political instability in neighboring regions.12

The initial phase of expansion was led by the Rashidun caliphs, who unified Arab tribes and directed their military efforts northward. This movement coincided with a period of significant exhaustion and decline for the Byzantine and Sasanian empires, whose long-standing conflicts had weakened their border defenses. Arab forces successfully captured key cities such as Damascus and Jerusalem, eventually leading to the collapse of the Sasanian Empire by 651 CE.3145

Under the subsequent Umayyad dynasty, the Islamic state expanded rapidly, reaching as far west as Morocco and Spain, and eastward into Sindh and Transoxania. Over the following centuries, the faith continued to spread through trade networks, the migration of Turkic peoples, and the influence of merchants in regions such as Southeast Asia.462