The Persatuan Islam (Islamic-Union) was a small group of Indonesian Muslim activists during the period 1923-1957. Their efforts involved them in the great disputes of the time, namely the shape of the emerging Indonesian state as the region broke loose from colonial control, and the direction of Islamic discourse in that new nation. Deeply ideological, these activists called themselves ''radical-revolutionaries''. Their outlook, starting as a manifestation of Islamic Modernism, later became a form of Islamic Neo-Fundamentalism. The views raised by the group were not generally accepted, as elites with other outlooks gained control of the nationalist agenda and the direction of the Indonesian Muslim community. The story of these activists, however, tells us much about the context of both Indonesian nationalism and Indonesian Islam as both developed during the first half of the 20th century.