This year marks the centennial of an explosive episode in modern Christian history. In July 1913, a prophetic evangelist named William Wadé Harris began his march across the French colony of Ivory Coast, calling people to live purely and to reject pagan religion. The astonishing impact he achieved suggests the deep popular thirst for his words and for the distinctly African style in which he clothed it. Some observers claimed he won 100,000 converts within a few months—until panicked French authorities drove him out of the country. Although prophets abounded in 20th-century Africa, Harris’s sweeping religious revolution marked the beginning of a critical new phase of mass evangelization.