The Spread and Influence of Islam Islam continued to extend its influence over the next several centuries. It spread east across South Asia to the islands of Indonesia. It moved north into Turkey and the Balkans region of Europe. It also expanded rapidly along the east coast of Africa and into the African interior, south of the Sahara.
Islam was a missionary religion, seeking to win converts, particularly in areas where polytheism prevailed. Muslims sometimes waged “holy war,” clashing with followers of other religions, including Christians. But they also respected Christians and Jews as people of faith and often lived alongside them in peace.
Today, with over a billion followers, Islam is the second largest religion in the world. More than a religion, however, it is a way of life. In Muslim lands, Islam has had a profound impact on culture, society, and politics. Shari’ah, Islamic law based on the Qur’an and Sunnah, provides guidance on all aspects of life, from clothing and food to education and finance. Shari’ah also forms the basis of legal codes in many Muslim countries.