The Catholic Church considers that it began on Pentecost when, according to scriptural accounts, the apostles received the Holy Spirit and emerged from hiding following the death and resurrection of Jesus to preach and spread his message. According to historians, the apostles traveled to northern Africa, Asia Minor, Arabia, Greece, and Rome to found the first Christian communities, over 40 of which had been established by the year 100. At first, Christians continued to worship alongside Jewish believers, but within twenty years of Jesus' death, Sunday was being regarded as the primary day of worship because it was revered as the day of Jesus' Resurrection. From as early as the first century, the Church of Rome was recognized as a doctrinal authority because it was believed that the Apostles Peter and Paul had led the Church there.

The apostles convened the first Church council, the Council of Jerusalem, in or around the year 50 to reconcile differences concerning the evangelization of Gentiles. Although competing forms of Christianity emerged early and persisted into the fifth century, there was broad doctrinal unity within the mainstream churches. From the year 100 onward, teachers like Ignatius of Antioch and Irenaeus defined Catholic teaching in stark opposition to Gnosticism. The Roman Church retained the practice of meeting in ecumenical councils to ensure that any internal doctrinal differences were quickly resolved. In the first few centuries of its existence, the Church formed its teachings and traditions into a systematic whole under the influence of theological apologists such as Pope Clement I, Justin Martyr and Augustine of Hippo.

Because early Christians refused to offer sacrifices to the Roman gods or to defer to Roman rulers as gods, they were frequently subject to persecution. This began under Nero in the first century and culminated in the great persecution of Diocletian and Galerius, which was seen as a final attempt to wipe out Christianity. Nevertheless, Christianity continued to spread and was eventually legalized in 313 under Constantine I's Edict of Milan.

In 325, the First Council of Nicaea convened in response to the threat of Arianism and formulated the Nicene Creed as a basic statement of Christian belief. Emperor Constantine I commissioned the first Basilica of St. Peter and several other sites of lasting importance to Christianity. By this time, the altar as the focal point of each church, the sign of the cross, and the liturgical calendar had been established. In 380, Christianity was declared the sole religion of the Empire. In subsequent decades a series of Ecumenical councils codified critical elements of the Church's theology. The Council of Rome in 382 listed the accepted books of the Old and New Testament and in 391 this Biblical canon, was translated into the common language of Latin creating the Vulgate. The Councils of Ephesus in 431, and Chalcedon two decades later, clarified the nature of Jesus' incarnation. These definitions sparked Monophysite disagreements which led to the first of the Oriental Orthodox Churches breaking away from the Catholic Church.

Early Middle Ages

Further information: Middle Ages and Christian monasticism

After the fall of the Western Roman Empire in 476, the Catholic faith competed with Arianism for the conversion of the barbarian tribes.^[215] The 496 conversion of Clovis I, pagan king of the Franks, marked the beginning of a steady rise of the Catholic faith in the West.

In 530, Saint Benedict wrote his monastic Rule, which became a blueprint for the organization of monasteries throughout Europe. The new monasteries preserved classical craft and artistic skills while maintaining intellectual culture within their schools, scriptoria and libraries. As well as providing a focus for spiritual life, they functioned as agricultural, economic and production centers, particularly in remote regions, becoming major conduits of civilization. From 590 Pope Gregory the Great dramatically reformed church practice and administration, launching renewed missionary efforts. These were complemented by the Hiberno-Scottish missions from the Celtic monasticism of the British Isles. Missionaries such as Augustine of Canterbury, Saint Boniface, Willibrord and Ansgar took Christianity to the Anglo–Saxons and other Germanic peoples. Later missions reached the Slavs and other Scandinavians. In the same period the Visigoths and Lombards moved from Arianism toward Catholicism, and in Britain the full reunion of the Celtic churches with Rome was effectively marked by the Synod of Whitby in 664.

In the early 700s, iconoclasts, supported by the Eastern Emperors, and iconodules, supported by the Western Church, fought over the use of images in religious worship. The dispute was resolved in 787 when the Second Council of Nicaea ruled in favor of icons. This was just one of many disputes between the Eastern and Western Churches, which were growing apart during this time. Charlemagne, who had been crowned in 800 by the pope attempted to unify Western Europe through the common bond of Christianity, creating an improved system of education and establishing unified laws. However imperial interest created a problem for the church as succeeding emperors sought to impose increasingly tight control over the popes. Disagreements between the Eastern and Western churches arose again in 858, when Patriarch Ignatius of Constantinople, favored by the pope, was deposed for the more extreme Photios. The pope declared the election of Photios invalid and excommunicated him. The consequent long-running dispute added to the growing alienation between the churches.

After a dispute over whether Constantinople or Rome held jurisdiction over the church in Sicily, the two Churches mutually excommunicated each other in 1054, resulting in the East-West Schism. The Western (Latin) branch of Christianity has since become known as the Catholic Church, while the Eastern (Greek) branch became known as the Eastern Orthodox Church. The Second Council of Lyon (1274) and the Council of Florence (1439) both failed to heal the schism. Some Eastern churches have subsequently reunited with the Catholic Church. In spite of attempts at reunification, the two churches remain in schism, although excommunications were mutually lifted in 1965.

High Middle Ages

Further information: High Middle Ages

The Cluniac reform of monasteries that had begun in 910 sparked widespread monastic growth and renewal. Monasteries introduced new technologies and crops, fostered the creation and preservation of literature and promoted economic growth. Monasteries, convents and cathedrals still operated virtually all schools and libraries. After 1100, some of these higher schools developed into universities, the direct ancestors of the modern Western institutions. Notable theologians such as Thomas Aquinas worked at these universities and his Summa Theologica was a key intellectual achievement in its synthesis of Aristotelian thought and Christianity.

In 1095, Byzantine emperor Alexius I appealed to Pope Urban II for help against Muslim invasions, which caused Urban to launch the First Crusade, hoping to bring about reconciliation with Eastern Christianity. The series of military campaigns that followed were intended to return the Holy Land to Christian control. The goal was not permanently realized, and episodes of brutality committed by the armies of both sides left a legacy of mutual distrust between Muslims and Western and Eastern Christians. The sack of Constantinople during the Fourth Crusade left Eastern Christians embittered, despite the fact that Pope Innocent III had expressly forbidden any such attack.

Reform efforts sparked by Cluny intensified internal Church efforts to eliminate the practice of lay investiture, or the practice of laymen selecting bishops. Considered by reformers to be a source of church corruption, lay investiture was a powerful source of dominance over the Church by secular rulers.^[245] Pope Gregory VII issued a decree against the practice in 1075 which contributed to a century and a half long struggle between popes and secular rulers. The matter was eventually settled with the Concordat of Worms in 1122 which decreed that elections of bishops would be conducted under canon law. Later, the Cistercian monk Bernard of Clairvaux's influence led to the founding of eight new monastic orders founded in the 12th century, including the Military Knights of the Crusades. In the following century, new mendicant orders were founded by Francis of Assisi and Dominic de Guzmán which brought consecrated religious life into urban settings.

Twelfth century France witnessed the emergence of Catharism, a belief which accepted suicide and denied the value of Church sacraments. After a papal legate was murdered by the Cathars in 1208, Pope Innocent III declared the Albigensian Crusade. Abuses committed during the crusade prompted Innocent III to informally institute the first papal inquisition to prevent future abuses and to root out the remaining Cathars. Formalized under Gregory IX, this Medieval inquisition executed an average of three people per year for heresy at its height.

Over time, other inquisitions were launched by the Church or secular rulers to prosecute heretics, to respond to the threat of Muslim invasion or for political purposes. In the 14th century, King Philip IV of France created an inquisition for his suppression of the Knights Templar. King Ferdinand and Queen Isabella formed an inquisition in 1480, originally to deal with distrusted ex-Jewish and ex-Muslim converts. Over a 350-year period, the Spanish Inquisition executed between 3,000 and 4,000 people, representing around two percent of those accused. In 1482 Pope Sixtus IV condemned the excesses of the Spanish Inquisition, but Ferdinand ignored his protests.^[257] Historians note that for centuries Protestant propaganda and popular literature exaggerated the horrors of the inquisitions in an effort to associate the entire Catholic Church with crimes most often committed by secular rulers. Over all, one percent of those tried by the inquisitions received death penalties, leading many scholars to consider them rather lenient when compared to the secular courts of the period. The inquisition played a major role in the final expulsion of Islam from the kingdoms of Sicily and Spain.

Driven by political instability in Rome, in 1309 Clement V became the first of seven popes to reside under French influence in the fortified city of Avignon.^[263] What became known as the Avignon Papacy ended in 1378 when, at the urging of Catherine of Siena and others, the papacy finally returned to Rome. With the death of Pope Gregory XI later that year, the papal election was disputed. Supporters of Italian and French-backed candidates were unable to come to agreement, resulting in the 38 year long Western schism with separate claimants to the papacy in Rome and Avignon. Efforts at resolution were further complicated when a third, compromise, pope was elected in 1409. The matter was finally resolved in 1417 at the Council of Constance where the cardinals called upon all three claimants to the papal throne to resign, and held a new election naming Martin V pope.

Late Medieval and Renaissance

Main articles: Reformation, English Reformation, and Counter-Reformation

Further information: Roman Catholic Church and colonialism and Catholicism and the wars of religion

Beginning in the late 15th century, European explorers and missionaries spread Catholicism to the Americas, Asia, Africa and Oceania. Pope Alexander VI had awarded colonial rights over most of the newly discovered lands to Spain and Portugal. Under the patronato system, however, state authorities, not the Vatican, controlled all clerical appointments in the new colonies. In December 1511, Antonio de Montesinos, a Dominican friar, openly rebuked the Spanish rulers of Hispaniola for their "cruelty and tyranny" in dealing with the American natives. King Ferdinand enacted the Laws of Burgos and Valladolid in response. However enforcement was lax, and while some historians blame the Church for not doing enough to liberate the Indians, others point to the Church as the only voice raised on behalf of indigenous peoples. The issue resulted in a crisis of conscience in 16th-century Spain. The reaction of Catholic theologians, such as Bartolome de Las Casas and Francisco de Vitoria, led to debate on the nature of human rights^[271] and the birth of modern international law.

In 1521 the Spanish explorer Ferdinand Magellan made the first Catholic converts in the Philippines. The following year, the first Franciscan missionaries arrived in Mexico, establishing schools, model farms and hospitals. When some Europeans questioned whether the Indians were truly human and worthy of baptism, Pope Paul III in the 1537 bull Sublimis Deus confirmed that "their souls were as immortal as those of Europeans" and they should neither be robbed nor turned into slaves. Over the next 150 years, missions expanded into southwestern North America. Native people were often legally defined as children, and priests took on a paternalistic role, sometimes enforced with corporal punishment. Elsewhere, Portuguese missionaries under the Spanish Jesuit Francis Xavier evangelized in India and Japan. By the end of the 16th century tens of thousands of Japanese followed Roman Catholicism. Church growth came to a halt in 1597 under the Shogun Tokugawa Iemitsu who, in an effort to isolate the country from foreign influences, launched a severe persecution of Christians. Despite enforced isolation, a minority Christian population survived into the 19th century.

In 1509, the most famous scholar of the age, Erasmus, wrote In Praise of Folly, a work which captured a widely held unease about corruption in the Church. The Council of Constance, the Council of Basel and the Fifth Lateran Council had all attempted to reform internal Church abuses but had failed. As a result, rich, powerful and worldly men like Roderigo Borgia (Pope Alexander VI) were able to win election to the papacy. In 1517, Martin Luther included his Ninety-Five Theses in a letter to several bishops. His theses protested key points of Catholic doctrine as well as the sale of indulgences. Huldrych Zwingli, John Calvin, and others further criticized Catholic teachings. These challenges developed into the Protestant Reformation. In Germany, the reformation led to a nine-year war between the Protestant Schmalkaldic League and the Catholic Emperor Charles V. In 1618 a far graver conflict, the Thirty Years' War, followed. In France, a series of conflicts termed the French Wars of Religion were fought from 1562 to 1598 between the Huguenots and the forces of the French Catholic League. King Henry IV's 1598 Edict of Nantes, which granted civil and religious toleration to Protestants was hesitantly accepted by Pope Clement VIII.

The English Reformation under Henry VIII, began more as a political than theological dispute. When the annulment of his marriage was denied by the pope, Henry had Parliament pass the Acts of Supremacy which made him, and not the pope, head of a new Church of England. Although he strove to maintain the substance of traditional Catholicism, Henry initiated and supported the confiscation and dissolution of monasteries, friaries, convents and shrines throughout England, Wales and Ireland. Under Henry's daughter, Mary I, England was reunited with Rome, but the following monarch, Elizabeth I, restarted a separate church which outlawed Catholic priests and prevented Catholics from educating their children and taking part in political life until the Catholic Emancipation Act of 1829 began the process of eliminating many of the anti–Catholic laws.

The Catholic Church responded to doctrinal challenges and abuses highlighted by the Reformation at the Council of Trent (1545–1563), which became the driving force of the Counter–Reformation. Doctrinally, it reaffirmed central Catholic teachings such as transubstantiation, and the requirement for love and hope as well as faith to attain salvation It also made important structural reforms, most importantly by improving the education of the clergy and laity and consolidating the central jurisdiction of the Roman Curia. New religious orders were founded, including the Theatines, Barnabites and Jesuits, some of which became the great missionary orders of later years.^[302] The writings of figures such as Teresa of Avila, Francis de Sales and Philip Neri spawned new schools of spirituality within the Church. To popularize Counter-Reformation teachings, the Church encouraged the Baroque style in art, music and architecture.

Enlightenment

See also: French Revolution, Jesuit Reductions, and Chinese Rites controversy

Toward the latter part of the 17th century, Pope Innocent XI reformed abuses by the Church, including simony, nepotism and the lavish papal expenditures that had caused him to inherit a papal debt. He promoted missionary activity around the world, tried to unite Europe against the Turkish invasions, and condemned religious persecution of all kinds. In 1685 King Louis XIV of France revoked the Edict of Nantes, ending a century-long experiment in religious toleration. This and other religious conflicts of the Reformation era provoked a backlash against Christianity, which helped spawn the violent anti-clericalism of the French Revolution. Direct attacks on the wealth of the Church and associated grievances led to the wholesale nationalisation of church property in France. Large numbers of French priests refused to take an oath of compliance to the National Assembly, leading to the Church being outlawed and replaced by a new religion of the worship of "Reason". Napoleon later re-established the Catholic Church in France through the Concordat of 1801. The end of the Napoleonic wars brought Catholic revival, renewed enthusiasm, and new respect for the papacy.

In the Americas, Franciscan priest Junípero Serra founded a series of new missions in cooperation with the Spanish government and military. These missions brought grain, cattle and a new way of living to the Indian tribes of California. San Francisco was founded in 1776 and Los Angeles in 1781. However, in bringing Western civilization to the area, the missions have been held responsible for the loss of nearly a third of the native population, primarily through disease.

In South America, Jesuits missionaries protected native peoples from enslavement by establishing semi-independent settlements called reductions. Pope Gregory XVI, challenging Spanish and Portuguese sovereignty, appointed his own candidates as bishops in the colonies, condemned slavery and the slave trade in 1839 (papal bull In Supremo Apostolatus), and approved the ordination of native clergy in spite of government racism.

In China, however, the Chinese Rites controversy led the Kangxi Emperor to outlaw Christian missions in 1721. This controversy added fuel to growing criticism of the Jesuits, who were seen to symbolize the independent power of the Church, and in 1773 European rulers united to force Pope Clement XIV to dissolve the order. The Jesuits were eventually restored in the 1814 papal bull Sollicitudo omnium ecclesiarum.

Industrial age

See also: History of Mexico, Pope Pius XII, and Cultural Revolution

The latter part of the 19th century saw important church developments. In 1870, the First Vatican Council affirmed the doctrine of papal infallibility when exercised in specifically defined pronouncements. Controversy over this and other issues resulted in a small breakaway movement called the Old Catholic Church. Later, the Industrial Revolution brought growing concern about the deteriorating working and living conditions of urban workers. In 1891, Pope Leo XIII published the encyclical Rerum Novarum which set out Catholic social teaching in terms that rejected socialism but advocated the regulation of working conditions, the establishment of a living wage and the right of workers to form trade unions. By the close of the 19th century, new technologies and superior weaponry had allowed European powers to gain control of most of the African interior. The new rulers introduced a cash economy which required African people to become literate, and so created a great demand for schools. At the time, the only possibility open to Africans for a western education was through Christian missionaries. Catholic missionaries followed colonial governments into Africa, and built schools, hospitals, monasteries and churches.

In Latin America, a succession of anti-clerical regimes came to power beginning in the 1830s. One such regime emerged in Mexico in 1860. Church properties were confiscated and basic civil and political rights were denied to religious orders and the clergy. The even more severe Calles Law introduced during the rule of atheist Plutarco Elías Calles eventually led to the "worst guerilla war in Latin American History", the Cristero War. Between 1926 and 1934, over 3,000 priests were exiled or assassinated. In an effort to prove that "God would not defend the Church", Calles ordered Church desecrations where services were mocked, nuns were raped and captured priests were shot. Calles was eventually deposed and despite the persecution, the Church in Mexico continued to grow. A 2000 census reported that 88 percent of Mexicans identify as Catholic.^[323] In the twentieth century, General Juan Perón's, Argentina and Fidel Castro's Cuba saw extensive persecution of the priesthood, and confiscation of Catholic properties.^{[324] [325]} In Europe a particularly violent outbreak of anti-clerical persecution took place in 1936 Spain. Because priests and nuns were symbols of conservatism, they were murdered in "large numbers" during the Spanish Civil War by republicans and anarchists. Confiscation of Church properties and restrictions on people's religious freedoms have generally accompanied secularist and Marxist-leaning governmental reforms.

In the 1937 encyclical Mit brennender Sorge, drafted by the future Pope Pius XII, Pope Pius XI warned Catholics that antisemitism is incompatible with Christianity. Read from the pulpits of all German Catholic churches, it described Hitler as an insane and arrogant prophet and was the first official denunciation of Nazism made by any major organization. Nazi reprisals against the Church in Germany soon followed, including "staged prosecutions of monks for homosexuality, with the maximum of publicity". When Dutch bishops protested against the wartime deportation of Jews, the Nazis responded with harsher measures against them. In Poland, the Nazis murdered over 2,500 monks and priests. The records of Dachau concentration camp alone, list 2,600 Roman Catholic priests who were incarcerated in the Priester-Block. In Stalin's Russia an even more severe persecution occurred. In the years after World War II historians such as David Kertzer accused the Church of encouraging centuries of antisemitism, and Pope Pius XII of not doing enough to stop Nazi atrocities. Prominent members of the Jewish community such as Albert Einstein contradicted the criticisms and spoke highly of Pius' efforts to protect Jews, while others noted that "hundreds of thousands" of Jews were saved by the Church. Even so, in 2000 Pope John Paul II on behalf of all people, apologized to Jews by inserting a prayer at the Western Wall that read "We're deeply saddened by the behavior of those in the course of history who have caused the children of God to suffer, and asking your forgiveness, we wish to commit ourselves to genuine brotherhood with the people of the Covenant. The aftermath of World War II saw atheistic communist governments in Eastern Europe severely restrict religious freedoms. The Church's resistance and the leadership of Pope John Paul II have been credited with hastening the downfall of communist governments across Europe in 1991, even though some priests collaborated with the regime.

The Communist rise to power in China of 1949 led to the expulsion of all foreign missionaries, "often after cruel and farcical 'public trials'". In an effort to further detach Chinese Catholics, the new government created the Patriotic Church independent of the worldwide Catholic Church. Rome subsequently rejected its bishops. The Cultural Revolution of the 1960s encouraged gangs of teenagers to eliminate all places of worship and turn their occupants into labourers. When Chinese churches eventually reopened they remained under the control of the Communist party's Patriotic Church, and many Catholic pastors and priests continued to be sent to prison for refusing to break allegiance with Rome.