Maximum Illud is an Apostolic Letter of Pope Benedict XV issued on November 30, 1919 ,in the sixth year of his pontificate. It deals with the Catholic missions after World War I. Pope Benedict XV recalled the great Apostles of the Gospel who contributed much to the Expansion of Missions . He reviewed the recent history of the missions and stated the purpose of the Apostolic letter. The encyclical first turned to the bishops and superiors in charge of the Catholic missions, noting the need to train local clergy. Catholic missionaries are reminded that their goal is a spiritual one, which must be carried out in a self-less way.