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The history of the Church in the Twentieth Century is best studied not by examining the religious events in the world country by country but by reviewing the activities of the popes during their respective reigns. The last pope of the nineteenth century was Pope Leo XIII, who died in 1903. This discussion on the history of the Church in the Twentieth Century will, therefore, continue with his successor, Pope St. Pius X. 


Pope St. Pius X (1835-1914)


  • He ordered reforms in sacred music in the motu proprio, Tra Le Sollecitudini (1903), which favored the use of the Gregorian chant in liturgical services.

  • He created a commission toward the codification of Canon Law in the motu proprio Arduum sane munus (1904).

  • He promoted the frequent and daily reception of the Holy Eucharist in the decree Sacra Tridentina Synodus (1905). See the English translation here, starting on p. 24.

  • He advocated the zealous teaching of catechism in Acerbo Nimis (1905).

  • He recommended the systematic study of Sacred Scriptures in the seminaries in his Apostolic Letter, Quoniam in Re Biblica (1906). Three years later, he established the “Bible Institute” in Rome.

  • He condemned Modernism by publishing the encyclical Pascendi Dominici Gregis (1907) and by approving the decree Lamentabili sane (1907), otherwise known as the "Syllabus Condemning the Errors of the Modernists." In 1910, through the motu proprio Sacrorum Antistitum, he also required all clergy, pastors, confessors, preachers, religious superiors, and professors in philosophical-theological seminaries to take the Oath against Modernism.

  • He permitted children to receive Holy Communion in the decree Quam Singulari (1910), for which he is still remembered as the “Pope of the Eucharist.”

  • He filled the Apostolic Palace with refugees after the 1908 Messina earthquake. See Pope Pius X and the Earthquake of 1908–1910.

  • He reformed the Roman breviary in the Apostolic Constitution Divino Aflatu (1911).

  • He insisted that Thomistic philosophy be the foundation of theological studies in his encyclical, Doctoris Angelici (1914).

  • He died on August 20, 1914, heartbroken due to the outbreak of WWI, which he tried to prevent. 


Pope St. Pius X (digitally colored)

Picture taken by some priests from the Society of Jesus, Freiburg in Breisgau, Oct., 1903

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Pope Benedict XV

Photo, circa 1915. Derived from U.S. Library of Congress

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Pope Benedict XV (1854-1922)

  • He maintained a position of neutrality during WWI. Because he was the pope of combatants on both sides of the war, he offered to be the mediator between the warring nations so that the war would end, but the nations refused to accept his offer, and the war continued.

  • He worked to alleviate hunger among the German people when the Allies blocked their country. He helped to relocate wounded soldiers to neutral countries and provided civilian refugees with the necessities of life.

  • He issued the 1917 Code of Canon Law, which was begun by a commission created by Pope St. Pius X.

  • He prayed to the Virgin Mary for peace on May 5, 1917. Then, on May 13, the Virgin Mary appeared to three shepherd children in Fatima, Portugal, and asked for prayers, particularly the Rosary. On October 13, the Blessed Virgin performed the famous “Miracle of the Sun” apparitions and said the war would soon end. The war ended on November 11, 1918, leaving a total casualty count of 9 million dead and another 21 million wounded.

  • He canonized Saints Joan of Arc (patroness of France) and Margaret Mary Alacoque (promoter of devotion to the Sacred Heart) in 1920.

  • He wrote a celebrated encyclical on peace and Christian reconciliation, Pacem Dei Munus Pulcherrimum (1920).

  • He wrote an encyclical on St. Dominic, Fausto Appetente Die (1921).

Pope Pius XI (1857-1939)

  • He insisted that those studying for the priesthood should use St. Thomas Aquinas as their guide. See his encyclical, Studiorum Ducem (1923).

  • He created the Feast of Christ the King through his encyclical, Quas Primas (1925), to remind the world that Christ is King not only of individuals and families but of states and nations.

  • He promoted missionary efforts throughout the world and permitted the training of native clergy and the formation of native hierarchies in the Far East. For this, he was known as the “Pope of the Foreign Missions.” He wrote the encyclical on Catholic Missions, Rerum Ecclesiae, ordered the yearly celebration of Mission Sunday, and named St. Therese to be co-patron with St. Francis Xavier of all foreign missions in the decree Apostolicorum in Missionibus (1927).

  • He negotiated the Lateran Treaty of 1929, in which the Kingdom of Italy under Benito Mussolini recognized the Vatican City as an independent state under the sovereignty of the Holy See. The Vatican City included 160 acres of land, the Vatican Palace, the Vatican Gardens, the Castel Gandolfo (the summer palace of the popes), the Basilica of Saint Peter, and three more great churches: St. John Lateran, St. Mary Major, and St. Paul Outside-the-Walls.

  • He issued an important encyclical on the Christian education of youth, Divini illius Magistri (1929), and on Christian marriage, Casti Connubii (1930).

  • He wrote the encyclical Quadragesimo anno (1931), which condemned the excesses of capitalism and addressed the social evils of the day, such as unemployment, industrial disputes, etc.

  • He canonized Saint Bernadette Soubirous (1933), to whom the Blessed Virgin revealed her name as “The Immaculate Conception.” He also canonized St. Thomas More and other English martyrs in 1935.

  • He founded the Pontifical Academy of Sciences in 1936 and wrote an encyclical on the Rosary, Ingravescentibus Malis, in 1937.

  • He worked to alleviate the persecution of the Church in Mexico, Spain, and Russia and rallied to prevent the spread of atheistic communism in his encyclical, Divini Redemptoris (1937).

  • He condemned the Nazi regime in Germany in his encyclical Mit Brennender Sorge (1937). The German Reich forcibly annexed Austria into Nazi Germany in 1938 and took over a part of Czechoslovakia. These, plus the religious hostility against Catholics, distressed Pope Pius XI and hastened his death in 1939. He was very well-liked and sorely missed upon his death by Catholics, Protestants, and Jews alike.


Pope Pius XI

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Pope Pius XII

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Pope Pius XII (1876-1958)

  • He prayed for peace and worked to keep peace between nations, but world leaders did not listen, and World War II erupted. The fascist dictator, Benito Mussolini, sent Italian troops to Albania. Adolf Hitler sent German troops to Czechoslovakia and, in 1937, invaded Poland. In his encyclical, Summi Pontificatus (1939), Pope Pius XII asked the Catholic faithful to pray for peace, denounced the deification of the State, and pleaded for generosity toward nations, such as Poland, which were suffering the atrocities of the war. Catholics in the U.S. helped to provide relief work, which Pope Pius XII called to aid nations suffering from the war.

  • Although he was severely criticized for his silence during the Holocaust, there is evidence that he assisted the underground movement to help the Jews escape from the Nazis. Jewish defenders of Pope Pius said that his silence had been more beneficial to the Jews than an explicit condemnation of the Nazis. See, for example, Rabbi defends Pope Pius XII’s actions.

  • Amid the turbulence caused by the war, he managed to write important encyclicals: one on Sacred Scripture, Divino Afflante Spiritu (1943), and another on the Church as the Mystical Body of Christ, Mystici Corporis (1943). After the war, he also wrote one on the Divine Liturgy, Mediator Dei (1947).

  • He warned the world of the dangers of communism, and, in 1949, he decreed the penalty of excommunication for any Catholic who held formal allegiance to the Communist Party.

  • He claimed that in October and November 1950, he saw the “Miracle of the Sun” four times while at the Vatican Gardens. It was an apparition similar to that which happened in Fatima, Portugal, in 1917. See Pius XII Saw “Miracle of the Sun.”

  • He defined the dogma of the assumption of Mary in the encyclical Munificentissimus Deus (1950).

  • He clarified the position of the Church regarding the theory of evolution in his encyclical, Humani Generis (1950).

  • He canonized the first U.S. citizen saint, Mother Francis Xavier Cabrini in 1946, and Pope St. Pius X in 1954.

  • He proclaimed St. Bernard of Clairvaux Doctor of the Church in the encyclical, Doctor Mellifluus (1953).

  • He proclaimed Mary Queen of the World in the encyclical Ad Caeli Reginam (1954). In November of the same year, he elevated the church in Cova da Iria, where the Blessed Virgin appeared to the children of Fatima, to the status of a basilica.

  • He promoted the recitation of the Holy Rosary through his encyclical Ingruentium Malorum (1951) and the devotion to the Sacred Heart of Jesus through the encyclical Haurietis Aquas (1956). He also canonized St. Catherine Labouré (1806–1876).

  • He continued the missionary efforts of Pope Pius XI and consecrated the first native Chinese and Indian cardinals. However, he lived to see the communist persecution of the Church in China. See his encyclical, Ad Apostolorum Principis (1958).

Pope St. John XXIII (1881-1963)

  • He appealed to all Christians to reunite with the Catholic Church in his encyclical Ad Petri Cathedram (1959).

  • He convened the Synod of Rome in 1960, which promulgated 755 statutes that aimed to restore the pristine spirituality of the Catholic Church. Pope St. John had hoped that the Synod would serve as a preparation for, and a forerunner to, the larger Vatican Council that was to follow.

  • He issued a long and important encyclical about the Church as Mother and Teacher, Mater et Magistra (1961), which confirmed the social teachings of Popes Leo XIII, Pius XI, and Pius XII. Pope St. John appealed to affluent countries to aid the underdeveloped nations of the world.

  • He published the Apostolic Constitution, Veterum Sapientia (1962), which recommended the study of Latin for the clergy. Sadly, many bishops and clergy ignored this Apostolic Constitution.

  • He convoked and opened Vatican II in October 1962. One of the aims of the Council was to bring all separated Christians together. Pope St. John, therefore, invited leaders from Protestant and Orthodox Churches to attend the council as observers.

    • NOTE: Vatican II has often been blamed for the appalling state of the Church today. However, Vatican II made many excellent recommendations, but many of its recommendations contained “exceptions” whose implementation was left to the discretion of the bishops having jurisdiction. Many liberal bishops and church leaders with modernist leanings took advantage of these “loopholes” in the Vatican II documents and started an aggiornamento not quite in keeping with the original intent and spirit of the council. The result was disastrous for the Church.

  • He canonized the Dominican cooperator brother, Martin de Porres, in 1962.

  • He wrote an encyclical entitled “Peace on Earth,” Pacem in Terris (1963), admonishing all nations to strive for peace and the betterment of humankind.

  • Pope St. John XXIII died of cancer while Vatican II was still in session. The world mourned his death because of his noted holiness and pastoral concern for the entire Church.


Pope St. John XXIII

By an unknown photographer


Pope St. Paul VI

Official Photograph from Vatican City, 1963

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Pope St. Paul VI (1897-1978)

  • He visited various places around the world in imitation of St. Paul, the great Apostle of the Gentiles. He visited the U.S. in 1965 and the Philippines in 1970. See Places Visited by Pope St. Paul VI.  

  • He met with Patriarch Athenagoras I of Constantinople in 1964, followed in 1965 by the mutual lifting and nullifying of the excommunication that the Catholic and Eastern Orthodox Churches hurled against each other in the Greek Schism of 1054.

  • He closed Vatican II on December 8, 1965, the feast of the Immaculate Conception.

  • He promulgated the Apostolic Constitution on Indulgences, Indulgentiarum Doctrina (1967). In the same year, the Congregation for the Doctrine of the Faith rescinded the Oath against Modernism required by Pope St. Pius X and replaced it with a Profession of Faith. The understanding is that although the word "modernism" does not explicitly appear in the new formula, priests and the clergy are still required by their profession of faith to fight against modernism. Unfortunately, the fact that it was no longer mandatory to take the oath gave the wrong signal to many clergy that the battle against modernism was now optional or that modernist doctrines and ideas may now be entertained or tolerated.

  • He published the motu proprio Credo of the People of God in 1968 to guide faithful Catholics on the true teachings of the Catholic Church, which the modernists are undermining in the name of Vatican II. This was followed by an encyclical, Humanae Vitae (1968), which contained the Church's teaching on contraception and birth control.

  • He promulgated the new Roman Missal in the Apostolic Constitution, Missale Romanum (1969). While the spirit behind the revision of the Roman Missal is valid, its implementation in the hands of the modernist clergy has resulted in abuses in the liturgy that have invited the criticism of more traditional Catholics.

  • He delivered a homily on June 29, 1972, in which he said that considering the present situation of the Church—which was characterized by doubt, uncertainty, and lack of trust in the Church—he perceived that the “smoke of Satan” (il fumo di Satana) had entered the Church. See Omelia di Paolo VI, 1972 (in Italian). Jimmy Akin posted an English summary of the homily on his blog. (See 1972 Homily.)

    • NOTE: Although Pope St. Pius X condemned modernism in 1907, it didn’t die and has gotten even stronger over the years. Even during the time of Pope St. Paul VI, there were many modernist followers, not only among the clergy but also at the higher levels of the hierarchy. Under the protection of the Holy Spirit, the Vatican II documents contained no explicitly modernist statements. However, the modernists in the Church thwarted the beneficial fruits of Vatican II by introducing novel ideas and practices and sneakily trumpeting them to the faithful as being “in the spirit of Vatican II.”

  • He issued an Apostolic Exhortation on the Right Ordering and Developing Devotion to the Blessed Virgin Mary, Marialis Cultus (1974). 

  • He wrote noteworthy encyclicals, such as the one on Christian Joy, Gaudete in Domino (1975), and Evangelization in the Modern World, Evangelii Nuntiandi (1975).

  • He approved and ordered the publication of the Declaration on Certain Questions Concerning Sexual Ethics, 1975.

  • He canonized the first native-born American saint, Elizabeth Ann Seton, in 1975.



Pope Bl. John Paul I (1912-1978)

  There is nothing much to say about Pope John Paul I because he was a pope for only 33 days on account of his sudden death. However, he was not the pope with the shortest reign. On record, the pope with the shortest reign was Pope Urban VII, who reigned for only 13 days. The pope with the longest reign was St. Peter, who reigned for 35 years.

Pope St. John Paul II (1920-2005)​​​​​​​


Pope St. John Paul II

Photo taken in Denver, Colorado, 1993

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  • He visited 129 countries during his papacy. See the List of pastoral visits of Pope John Paul II.

  • He explained the deposit of faith and guarded the tradition of the Church from errors through his extensive writings. He wrote 14 encyclicals, 15 apostolic exhortations, 11 apostolic constitutions, and 45 apostolic letters. See Encyclicals and Other Writings of Pope St. John Paul II.

  • He canonized 475 saints during his pontificate. See List of Saints canonized by JP2.

  • He visited his native Poland in 1979, which invigorated the Solidarity movement that later led to the collapse of communism in Europe.

  • He became a victim of an attempted assassination in St. Peter’s Square in 1981 but mercifully forgave his assassin.

  • He appointed Cardinal Joseph Ratzinger (the future Pope Benedict XVI) as prefect of the Congregation for the Doctrine of the Faith in 1981.

  • In 1984, he granted priests, through a special indult, the faculty of celebrating Mass according to the 1962 Roman Missal of Pope John XXIII. Then, in 1988, he issued a motu proprio, Ecclesia Dei, in which he encouraged bishops to make generous use of this faculty for the benefit of the faithful who wanted it.

  • He clarified the Church's position on homosexuality in a Letter to the Bishops of the Catholic Church on the Pastoral Care of Homosexual Persons, 1986.

  • He promoted ecumenical and interfaith initiatives in 1986 by inviting the various religious leaders of the world for a Day of Prayer for Peace. The event, which was attended by 32 Christian and 11 non-Christian religious organizations, invited criticism from some quarters because the sight of various religious leaders praying together gave the impression of "syncretism," or the false idea that all religions are on the same level. However, the saintly pope clarified that "coming together to pray" is not the same thing as "praying together." The various religious groups prayed in their own way and, therefore, weren't really praying together with the rest. Their togetherness should not be interpreted as an attempt toward a fusion of different faiths, but only as a sign of their common longing for peace. The Prayer for Peace was repeated in 1993 to end the war in Bosnia. And, after the 9/11 terrorist attacks in 2001, Pope St. John Paul II again called for a Prayer for Peace in 2002 to stop using religion as a pretext for fomenting violence. All ecumenical events were held in Assisi, Italy.

  • He authorized the writing and publication of The Catechism of the Catholic Church, which is an updated catechism based on Vatican II. See the Apostolic Constitution Fidei Depositum (1992).

  • In 1997, he declared St. Thérèse of Lisieux (1873–1897) a Doctor of the Church and, in 2000, canonized St. Faustina Kowalska (1905–1938), a Polish nun who is known to the Catholic world as the Apostle of Divine Mercy.

  • He asked forgiveness of those offended by the sins of the Church throughout its long history. See the Homily of the Holy Father, March 2000.

  • He asked for forgiveness for sexual abuse committed by the clergy in 2001. See Pope sends first e-mail apology. 

  • In 2002, he added the Luminous Mysteries (or the "Mysteries of Light") to the Holy Rosary in his Apostolic Letter, Rosarium Virginis Mariae. In the same year, he also canonized St. Pio of Pietrelcina (1887–1968), popularly known as "Padre Pio."

  • He suffered from Parkinson’s disease in his last years and died on April 28, 2005, with about 3 million pilgrims traveling to Rome to pay their respects. He was liked by everyone, even those of other religions.

Saints of the Twentieth Century

Besides Popes Pius X, John XXIII, Paul VI, John Paul I, and John Paul II, some of the famous saints of the twentieth century include the following:

  • St. Maria Goretti (1890–1902) 

  • St. Faustina Kowalska (1905–1938) 

  • St. Padre Pio (1887–1968)

  • St. Mother Teresa of Kolkata (1910–1997) 

  • Bl. Carlo Acutis (1991–2006).

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