Islam spread through military conquest, trade, pilgrimage, and missionaries.
Arab Muslim forces conquered vast territories and built imperial structures over time.
Most of the significant expansion occurred during the reign of the Rashidun from 632 to 661 CE, which was the reign of the first four successors of Muhammad.
The caliphate—a new Islamic political structure—evolved and became more sophisticated during the Umayyad and Abbasid caliphates.