The popes at the end of the 19th cent. turned more toward pure spiritual and moral leadership in a tangled world. The growth of Catholicism in areas outside Europe tended to make the pope more and more the single unifying force in the church and therefore fundamentally an international figure. A singular succession of dynamic popes strengthened this effect; Leo XIII, Pius X, Benedict XV, Pius XI, Pius XII, John XXIII, Paul VI, and John Paul II all strove to reorient the church in the modern world, to combat secularism, and to extend Roman Catholic morality in social relations. The social encyclical of Leo XIII, Rerum Novarum (1891), was echoed in the encyclical of Pius XI, Quadragesimo Anno (1931); reinforced and restated by John XXIII in Mater et Magistra (1961); reaffirmed once again by Paul VI in Populorum Progressio (1967); and restated several times by John Paul II in Laborem Exercens (1981), Sollicitudo Rei Socialis (1987), and Centessimus Annus (1991, the 100th anniversary of Leo's encyclical). The recommendations made in these encyclicals are international in scope, and the international prestige of the papacy has been increased by its steady advocacy of peace and its aid to the oppressed and destitute of the world.
Politically, the role of the papacy has been more controversial. Pius XII was criticized by some for not condemning more strongly the Nazi regime in Germany (especially in its persecution of the Jews); these critics suggest that he was far more implacably hostile to Communism. The encouragement of greater lay participation in the church itself (e.g., approval of the liturgical movement), fostering of the varied contributions of the parts of the church, desire to unite all Christians, encouragement of the "progressive" renewal within the church itself—all these came to the fore when Pope John XXIII convened the Second Vatican Council. The efforts of the council, under the close direction of John XXIII and Paul VI, to renew the spiritual and organizational life of the church had the paradoxical effect of increasing challenges to papal authority.
The council's stress on the collegiality of bishops and pope in the rule of the universal church led to the establishment of national conferences of bishops, a step that tended to disrupt the direct exercise of papal authority over individual bishops and increase the autonomy of local churches. Following the council there arose discussions among Catholic theologians of the limits of papal jurisdiction and infallibility. Paul VI attempted to uphold the primacy of the papal teaching office in his reassertion, in the encyclical Humanae Vitae (1968), of the traditional doctrine prohibiting artificial birth control; his attempt was met with subtle evasion by some of the national conferences of bishops and by open defiance by some priests and theologians.
John Paul I was pope for 34 days in 1978 before his death. The nearly three decade pontificate of his successor, John Paul II (r.1978–2005), was marked by an increased papal presence in the international sphere through extensive travel outside Rome. He also broadened international representation in the College of Cardinals and in the Roman Curia. Although John Paul II worked to implement the mandates of the Second Vatican Council, he firmly and successfully reasserted the primacy and authority of the pope and the Vatican while also convening an unprecedented number of consistories to advise him. The first non-Italian pope since Adrian VI (1522–23), John Paul II was also the first Polish and Slavic pope. He was succeeded in 2005 by Benedict XVI, a German who had worked closely with John Paul in the Curia. Benedict XVI largely continued the policies of his predecessor, but surprisingly for a pope who was generally a traditionalist, he broke 600 years of tradition and chose to resign (for reasons of age) in 2013. Benedict's successor, Francis, an Argentinian, was the first non-European elected in more than 1,000 years as well as the first person from the Americas and the first Jesuit to be elected.