“The Apostle to Islam”, Samuel Marinus Zwemer (1867 – 1952), was a missionary for over 40 years in Basrah, Bahrain, and Egypt. From 1929 to 1937 he was professor of history of religion and missions at Princeton Theological Seminary. He was appointed a member of the British Royal Geographic Society, and was editor of The Moslem World. Dr. Zwemer inspired many Christians to become missionaries to Muslims. [Some information from wikipedia “Samuel Marinus Zwemer”.]