Priesthood in the Catholic Church in the context of "Crusading"

Georges Henri Joseph Édouard Lemaître (/ləˈmɛtrə/ lə-MET-rə; French: [ʒɔʁʒ ləmɛːtʁ] ; 17 July 1894 – 20 June 1966) was a Belgian Catholic priest, theoretical physicist, and mathematician who made major contributions to cosmology and astrophysics. He was the first to argue that the recession of galaxies is evidence of an expanding universe and to connect the observational Hubble–Lemaître law with the solution to the Einstein field equations in the general theory of relativity for a homogenous and isotropic universe. That work led Lemaître to propose what he called the "hypothesis of the primeval atom", now regarded as the first formulation of the Big Bang theory of the origin of the universe.

Lemaître studied engineering, mathematics, physics, and philosophy at the Catholic University of Louvain and was ordained as a priest of the Archdiocese of Mechelen in 1923. His ecclesiastical superior and mentor, Cardinal Désiré-Joseph Mercier, encouraged and supported his scientific work, allowing Lemaître to travel to England, where he worked with the astrophysicist Arthur Eddington at the University of Cambridge in 1923–1924, and to the United States, where he worked with Harlow Shapley at the Harvard College Observatory and at the Massachusetts Institute of Technology (MIT) in 1924–1925.

The Crusading movement was a major religious, political and military endeavour of the Middle Ages—began in 1095 when Pope Urban II, at the Council of Clermont, proclaimed the First Crusade to liberate Eastern Christians from Muslim rule. He framed it as a form of penitential pilgrimage, offering spiritual rewards. By then, papal authority in Western Christendom had grown through church reforms, and tensions with secular rulers encouraged the notion of holy war—combining classical just war theory, biblical precedents, and Augustine's teachings on legitimate violence. Armed pilgrimage aligned with the era's Christocentric and militant Catholicism, sparking widespread enthusiasm. Western expansion was further enabled by economic growth, the decline of older Mediterranean powers, and Muslim disunity. These factors allowed crusaders to seize territory and found four Crusader states. Their defence inspired successive Crusades, and the papacy extended spiritual privileges to campaigns against other targets—Muslims in Iberia, pagans in the Baltic, and other opponents of papal authority.

The Crusades fostered distinctive institutions and ideologies, having a great impact on medieval Europe and the Mediterranean. Though aimed primarily at the warrior elite through appeals to chivalric ideals, they depended on broad support from clergy, townspeople, and peasants. Women, despite being discouraged, were involved as participants, proxies for absent crusaders, or victims. Although many crusaders were motivated by indulgences (remission of sins), material gain also played a part. Crusades were typically initiated through papal bulls, with participants pledging to join by "taking the cross"—sewing a cross onto their garments. Failure to fulfil vows could result in excommunication. Periodic waves of zeal produced unsanctioned "popular crusades".

Martin Luther (/ˈluːθər/ LOO-thər; German: [ˈmaʁtiːn ˈlʊtɐ] ; 10 November 1483 – 18 February 1546) was a German priest, theologian, author, hymnwriter, professor, and former Augustinian friar. Luther was the seminal figure of the Protestant Reformation, and his theological beliefs form the basis of Lutheranism. He is widely regarded as one of the most influential figures in Western and Christian history.

Born in Eisleben, Luther was ordained to the priesthood in 1507. He came to reject several teachings and practices of the contemporary Roman Catholic Church, in particular the view on indulgences and papal authority. Luther initiated an international debate on these in works like his Ninety-five Theses, which he authored in 1517. In 1520 Pope Leo X demanded that Luther renounce all of his writings, and when Luther refused to do so, excommunicated him in January 1521. Later that year, Holy Roman Emperor Charles V condemned Luther as an outlaw at the Diet of Worms. When Luther died in 1546, his excommunication by Leo X was still in effect.

The Mass is the central liturgical service of the Eucharist in the Catholic Church, in which bread and wine are consecrated and become the body and blood of Christ. As defined by the Church at the Council of Trent, in the Mass "the same Christ who offered himself once in a bloody manner on the altar of the cross, is present and offered in an unbloody manner". The Church describes the Mass as the "source and summit of the Christian life", and teaches that the Mass is a sacrifice, in which the sacramental bread and wine, through consecration by an ordained priest, become the sacrificial body, blood, soul, and divinity of Christ as the sacrifice on Calvary made truly present once again on the altar. The Catholic Church permits only baptised members in the state of grace (Catholics who are not in a state of mortal sin) to receive Christ in the Eucharist.

Many of the other sacraments of the Catholic Church, such as confirmation, holy orders, and holy matrimony, are generally administered within a celebration of Mass, but before the Second Vatican Council were often or even usually administered separately. The term Mass, also Holy Mass, is commonly used to describe the celebration of the Eucharist in the Latin Church, while the various Eastern Catholic liturgies use terms such as Divine Liturgy, Holy Qurbana, and Badarak, in accordance with each one's tradition.

In the liturgical traditions of the Catholic Church, the term ordination refers to the means by which a person is included in one of the holy orders of bishops, priests, or deacons. The teaching of the Catholic Church on ordination, as expressed in the 1983 Code of Canon Law, the Catechism of the Catholic Church, and Ordinatio sacerdotalis (an apostolic letter), is that only a Catholic male validly receives ordination (ex opere operato), and "that the Church has no authority whatsoever to confer priestly ordination on women and that this judgment is to be definitively held by all the Church's faithful." In other words, the male priesthood is not considered by the church a matter of policy but an unalterable requirement of God. As with priests and bishops, the church ordains only men as deacons.

Ignatius of Loyola SJ (/ɪɡˈneɪʃəs/ ig-NAY-shəs; Basque: Ignazio Loiolakoa; Spanish: Ignacio de Loyola; Latin: Ignatius de Loyola; born Íñigo López de Oñaz y Loyola; c. 23 October 1491 – 31 July 1556), venerated as Saint Ignatius of Loyola, was a Spaniard Catholic priest and theologian, who, with six companions, founded the religious order of the Society of Jesus (Jesuits), and became its first Superior General, in Paris in 1541.

Ignatius envisioned the purpose of the Society of Jesus to be missionary work and teaching. In addition to the vows of chastity, obedience and poverty of other religious orders in the church, Loyola instituted a fourth vow for Jesuits of obedience to the Pope, to engage in projects ordained by the pontiff. Jesuits were instrumental in leading the Counter-Reformation.

The Church of the Gesù (Italian: Chiesa del Gesù, pronounced [ˈkjɛːza del dʒeˈzu]), officially named Chiesa del Santissimo Nome di Gesù (English: Church of the Most Holy Name of Jesus), is a church located at Piazza del Gesù in the Pigna rione of Rome, Italy. It is the mother church of the Society of Jesus (best known as Jesuits). With its façade, described as "the first truly baroque façade", the church served as a model for innumerable Jesuit churches all over the world, especially in Central Europe and in Portuguese colonies. Its paintings in the nave, crossing, and side chapels became models for art in Jesuit churches throughout Italy and Europe, as well as those of other orders. The Church of the Gesù is one of the great 17th-century preaching churches built by Counter-Reformation orders like the Jesuits in the Centro Storico of Rome – the others being Sant'Ignazio, also of the Jesuits, San Carlo ai Catinari of the Barnabites, Sant'Andrea della Valle of the Theatines, and the Chiesa Nuova of the Oratorians.

First conceived in 1551 by Saint Ignatius of Loyola, the Spanish founder of the Society of Jesus active during the Protestant Reformation and the subsequent Catholic Counter-Reformation, the Gesù was also the home of the Superior General of the Society of Jesus until the wide suppression of the order in 1773. The church having been subsequently regained by the Jesuits, the adjacent palazzo is now a residence for Jesuit scholars from around the world studying at the Gregorian University in preparation for ordination to the priesthood.

Matteo Ricci SJ (Italian: [matˈtɛːo ˈrittʃi]; Latin: Matthaeus Riccius; 6 October 1552 – 11 May 1610) was an Italian Jesuit priest and one of the founding figures of the Jesuit China missions. He created the Kunyu Wanguo Quantu, a 1602 map of the world written in Chinese characters. In 2022, the Apostolic See declared its recognition of Ricci's heroic virtues, thereby bestowing upon him the honorific of Venerable.

Ricci arrived at the Portuguese settlement of Macau in 1582 where he began his missionary work in China. He mastered the Chinese language and writing system. He became the first European to enter the Forbidden City of Beijing in 1601 when invited by the Wanli Emperor, who sought his services in matters such as court astronomy and calendrical science. He emphasized parallels between Catholicism and Confucianism but opposed Buddhism. He converted several prominent Chinese officials to Catholicism. He also worked with several Chinese elites, such as Xu Guangqi, in translating Euclid's Elements into Chinese as well as the Confucian classics into Latin for the first time in history.

Pope Benedict XVI (born Joseph Alois Ratzinger; 16 April 1927 – 31 December 2022) was head of the Catholic Church and sovereign of the Vatican City from 2005 until his resignation in 2013. Following his resignation, he chose to be known as "pope emeritus", a title he held until his death on 31 December 2022.

Ordained as a priest in 1951 in his native Bavaria, Ratzinger embarked on an academic career and established himself as a highly regarded theologian by the late 1950s. He was appointed a full professor in 1958 when aged 31. After a long career as a professor of theology at several German universities, he was appointed Archbishop of Munich and Freising and created a cardinal by Pope Paul VI in 1977, an unusual promotion for someone with little pastoral experience. In 1981, he was appointed Prefect of the Congregation for the Doctrine of the Faith, one of the most important dicasteries of the Roman Curia. In 2002, he also became Dean of the College of Cardinals. Before becoming pope, he had been "a major figure on the Vatican stage for a quarter of a century"; he had had an influence "second to none when it came to setting church priorities and directions" as one of John Paul II's closest confidants. Following the death of John Paul II on 2 April 2005, a conclave elected Ratzinger as his successor on 19 April; he chose Benedict XVI as his papal name in honour of Benedict XV and Benedict of Nursia.