# History of Christianity

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The history of Christianity begins with the ministry of Jesus, a Jewish teacher and healer, who was crucified and died c. AD 30–33 in Jerusalem in the Roman province of Judea. Afterwards, his followers, a set of apocalyptic Jews, proclaimed him risen from the dead. Christianity began as a Jewish sect and remained so for centuries in some locations, diverging gradually from Judaism over doctrinal, social and historical differences. Despite the persecution of Christians in the Roman Empire, the faith spread as a grassroots movement that by the third century was established both in and outside the empire. New Testament texts were written and church government was loosely organized in its first centuries, though the biblical canon did not become official until 382.
Constantine the Great was the first Roman emperor to declare himself a Christian. In 313, he issued the Edict of Milan expressing tolerance for all religions. He did not make Christianity the state religion, but he did provide it with crucial support. Constantine called the first of seven ecumenical councils. Reaction to the fourth council produced the first split between Eastern and Western Christianity, creating the Church of the East. After 476, monks in the West preserved Western culture, spread Christianity across western Europe, and established the Christendom of the High Middle Ages that influenced every aspect of medieval European life.
Between 600 and 750, Christianity was in retreat in the Near and Middle East and North Africa, while the Eastern church prospered along the Silk Road, and all of the main trade routes of Central Asia, into Tibet and China, among the Mongols, the Nubian kingdoms, Ethiopia, Caucasian Armenia, and Georgia. Ongoing wars turned the Eastern Roman Empire into the Byzantine Empire. Between the ninth and twelfth centuries, politicization and Christianization formed the states of East-Central Europe. Byzantine missionaries there developed the Cyrillic script, which allowed the spread of literacy, literature, and culture in the Slavic countries and Russia. Western Christianity centralized and became bureaucratic, and by 1054, Eastern and Western Christianity had grown far enough apart that differences produced the East–West Schism creating Byzantine Orthodoxy. This did not prevent the request for aid by the Byzantines that led to the Crusades. Temporary reunion of East and West was achieved in 1452; it lasted until Constantinople fell in 1453 and Byzantium became part of the empire of the Ottoman Turks.
During the fourteenth and fifteenth centuries, various crises in Europe, coupled with growing criticism of the Catholic Church, led to the sixteenth-century Reformation. The Catholic Church responded in the Counter-Reformation. Royal houses already involved in disputes precipitated the European wars of religion. This was followed by the Age of Enlightenment and modern political concepts of tolerance. In the eighteenth century, biblical criticism was created, challenging literal interpretations of the Bible. Parts of Christianity influenced the American Revolution, worked for societal reforms, and formed an important part of the ideology of Abolitionism which shut down the Atlantic slave trade. Nineteenth-century Protestant missionaries shaped multiple societies through literacy and indigenization.
In the twentieth century, Christianity faced many challenges and conflicts both internal and external. Traditional Christianity declined in the West, while new forms developed. The centre of growth shifted from West to East and from the North to the Global South. In the twenty-first century, it is the world's largest religion with more than two billion Christians worldwide.

## Early Christianity (c. 27 – fourth century)
### The first century

Christianity began with the itinerant preaching of Jesus (c. 27–30), a Jewish man, who lived in the Roman province of Judea during the first century. Jesus' existence and his crucifixion are well attested. The religious, social, and political climate in Judea was extremely diverse and characterized by turmoil with numerous religious and political movements. One such movement, Jewish messianism, promised a messianic redeemer descended from King David who would save Israel. Christians saw Jesus of Nazareth as that Messiah.
Jesus saw his identity and mission, and that of his followers, in light of the present and future kingdom of God and the prophetic tradition of Israel. His followers believed God's spirit was incarnated (embodied) in Jesus and that after his crucifixion, he rose from the dead. The Christian church established incarnation and resurrection as its first doctrines, with baptism and the celebration of the Eucharist meal (Jesus's Last Supper) as its two primary rites and rituals.
The first Christian communities were predominantly Jewish. They gathered in small groups inside private homes, where the typical setting for worship was the communal meal. Small groups were self-organized with no central authority. Modeled after the synagogue, elders called presbyters or bishops, were overseers of the small groups, provided for the economic requirements of the meal, and for charitable distributions; any ceremonial role these early bishops took was initially connected to this more prosaic role.
Beginning with fewer than 1000 adherents, Christianity grew to around one hundred small household churches consisting of an average of seventy members each by the year 100. It spread through the dispersed peoples along the trade and travel routes followed by merchants, soldiers, and migrating tribes. In the first century it reached ancient Greece, and probably Alexandria, Egypt. Christianity was largely an urban religion. The largest cities in the empire had Christian congregations by the end of the first century. By the second century, smaller Christianized cities were clustered around them. Paul was one of several apostles who spread Christianity in the first century, making at least three missionary journeys and founding numerous churches in Asia Minor; Christianity in Antioch is mentioned in his epistles. Cities such as Antioch and Alexandria gradually became more influential than Jerusalem.
The Jews of Alexandria had produced a Greek translation of their Hebrew Bible between the third and first centuries BC which the apostles and early Christians used. Unlike Judaism, Christianity has no sacred language. In the early centuries, the languages most used to spread Christianity were Latin, Greek, and Syriac (a form of Aramaic). Christian writings in Koine Greek, including the four gospels (the accounts of Jesus's ministry), letters of Paul, and letters attributed to other early Christian leaders, were written in the first century and had considerable authority even in the formative period. The letters of the Apostle Paul sent to the early Christian communities were circulating in collected form by the end of the first century. First century Christians put these writings in a codex, the ancestor of modern books, and the Egyptian church likely invented the papyrus codex during the next decades.
At the Council of Jerusalem, (c. 49), the Jerusalem church gathered to determine if the increasing numbers of non-Jews needed to follow Jewish law. The council decided to allow Gentile Christians their form of Christianity and Jews theirs. The departure of Christians before the destruction of Jerusalem by the Romans in 70, alongside the development of what would become Rabbinic Judaism, disagreements about Jewish law, and insurrections against Rome, contributed to Jewish Christianity and Gentile Christianity growing apart. Nevertheless, Jewish Christianity remained influential in Palestine, Syria, and Asia Minor into the second and third centuries.

### Ante-Nicene period (100–312)

Christianity achieved critical mass in the years between 150 and 250, when it grew from fewer than 50,000 adherents to over a million. Paul's missionary journeys had spread the Christian faith east into Syria and Mesopotamia where the population spoke Aramaic, not Greek. Aramaic Christians were in Adiabene (northern Iraq) by the second century. By the third century, it had spread into North Africa and across the Mediterranean region, from Greece and Anatolia into the Balkans in the East and as far as Roman Britain in the northwest. Christianity's social impact, especially its charitable practices, contributed to its rapid spread, despite intense and continuing competition from traditional polytheism and alternative cults and creeds.
A more formal church structure grew over the second and third centuries AD, but at different times in different locations. Bishops were essential to the development of Christianity, and they rose in power and influence as they began to preside over larger areas with multiple churches. Early Christianity was open to everyone. Baptism was free, and there were no fees, which made Christianity more affordable than traditional Roman models.
Women comprised significant numbers of Christianity's earliest members. Women could attain greater freedom through religious activities than Roman customs otherwise permitted. Women in the church were prominent in church rolls, the Pauline epistles, and in early Christian art, while much early anti-Christian criticism was linked to "female initiative" indicating their role in the movement.
A key characteristic of early Christianity was its unique type of exclusivity. Believing was the crucial and defining characteristic of membership – believers were separated from the "unbelievers" and heretics by a strong social boundary. This exclusivity gave Christianity the psychological attraction of elitism.
The four gospels and the letters of Paul were generally regarded as authoritative, but other writings, such as the Book of Revelation and the epistles to the Hebrews, James, and I John, were assigned different degrees of authority. Gnostic texts challenged the physical nature of Jesus, Montanism suggested that the apostles could be superseded, and Monarchianism emphasized the unity of God over the Trinity. In the face of such diversity, unity was provided by the shared scriptures and the bishops. In the early church, canon law did not yet exist.
The Ante-Nicene period included sporadic but increasing persecution from Roman authorities, and the rise of Christian sects, cults, and movements. In the 250s, the emperors Decius and Valerian made it a capital offence to refuse to make sacrifices to Roman gods, resulting in widespread persecution of Christians. Official persecution reached its height under Diocletian in 303–311. Authorities in the Sasanian Empire also periodically persecuted Christians.
There are few early records of early Christian art. The oldest forms emerged in funerary environments c. 200. It typically fused Graeco-Roman style and Christian symbolism: the most common image was Jesus as the good shepherd.

## Late antiquity (313 – c. 600)

Late Antiquity was an age of change as Christianity became a permitted religion, then a favored one, and transformed in every capacity. In 313, the emperor Constantine, a self-declared Christian, issued the Edict of Milan expressing tolerance for all religions. Thereafter, he supported Christianity, giving bishops judicial power, and legally establishing them as equal to polytheistic priests. He devoted personal and public funds to building churches and endowed them with funds for maintenance and support of their clergy.
There were churches in the majority of Roman cities by the end of the fourth century. Even so, polytheism remained widespread for centuries, as late as the ninth century in Greece. There was no legislation forcing the conversion of pagans before the Eastern Emperor Justinian I (r. 527–565); religious violence in Late Antiquity was "mostly restricted to violent rhetoric" and was not otherwise a general phenomenon. However, there were hostile imperial laws aimed at suppressing sacrifice and magic that contributed to one of the most significant changes of this age; blood sacrifice had been a central rite of virtually all religious groups in the pre-Christian Mediterranean, but it disappeared by the end of the fourth century.
Christian art, literature and architecture blossomed under Constantine. The basilica, a type of Roman municipal court hall, became the model for Christian architecture. Frescoes, mosaics, statues, and paintings blended classical and Christian styles. Similarly, a hybrid form of poetry written in classical styles with Christian concepts emerged. In the late fourth century, Jerome was commissioned to translate the Greek biblical texts into the Latin language; this translation was called the Vulgate. Church fathers of this period, such as Augustine of Hippo, John Chrysostom, Gregory of Nyssa, Athanasius of Alexandria, Basil of Caesarea, Gregory of Nazianzus, Cyril of Alexandria, and Ambrose of Milan, wrote vast numbers of works, contributing to a golden age of writing.
Constantine and his successors attempted to fit the church into their political program. Church leaders responded by articulating the first limitations on a secular ruler's authority, arguing that religious authority must be separate from State authority. For most of Late Antiquity, the popes – the successors to Saint Peter as bishop of Rome – had limited influence, and did not yet have the power needed to break free of secular interference in church affairs. However, papal power began to rise in this age as eastern patriarchs looked to the Roman Pope to resolve disagreements.
In the fourth century, Augustine of Hippo argued that Jews should not be killed or forcibly converted, instead, they should be left alone because they preserved the teachings of the Old Testament and were "living witnesses" of the New Testament. Most Jews and Christians, (with the exception of the Visigoths in Spain), lived peacefully alongside each other into the High Middle Ages. The theology of supersessionism emerged claiming Christians had displaced the Jews as God's chosen people; many scholars attribute antisemitism to this concept while others distinguish between them.
Monasticism, which had begun early in Syria, was key to the development of Christianity. In Late Antiquity, these communities became associated with the urban holy places in Palestine (which became a center of pilgrimage), Cappadocia, Italy, Gaul, and Roman North Africa. In the 370s, Basil the Great founded the Basileias, a monastic community in Caesarea (Mazaca) that developed the first health care system for the poor which became the model of public hospitals into the modern day.

### After 476

After 476 and the breakup of the Western Roman Empire, there was no center of political power in the European West. The ensuing socio-political fragmentation left the church with responsibility for the folk. Thereafter, western Europe developed in a manner distinctively different from the remaining empire in the East. For the next five centuries, Western culture and civilization were preserved and passed on primarily by monks while the Eastern Roman Empire continued to be a Roman Empire with an emperor, a civil government, and a large army.
The religious policies of the Eastern Roman Emperor Justinian I (r. 527–565) reflected his conviction that the unity of the Empire presupposed unity of faith: he persecuted pagans and religious minorities and purged government and church bureaucracies of those who disagreed with him. He contributed to cultural development, and integrated Christian concepts with Roman law in his Corpus Juris Civilis which remains the basis of civil law in many modern states. In the 530s in Constantinople, he had the Hagia Sophia built, inventing pendentives: inverted triangles that allow a dome to be suspended. Many later Byzantine and Ottoman architects used the Hagia Sophia as a model. It was the world's largest cathedral for nearly a thousand years, and its dome remains the third largest in the modern world.
In Gaul, the Frankish king Clovis I converted to Catholicism; his kingdom became the dominant polity in the West in 507, gradually converting into a Christian kingdom over the next centuries. Papal influence rose as competition within the church continued to lead people to Rome to resolve their problems. Gregory the Great (590-604) gained prestige and power for the papacy by leading the response to invasion by the Lombards in 592 and 593, reforming the clergy, standardizing music in worship, sending out missionaries and founding new monasteries. Until 751, the Pope remained a subject of the Byzantine emperor.

### Geographical spread

Christianity continued to grow rapidly, both westwards and eastwards. Christians in Persia, (present-day Iraq), were deeply persecuted in Late Antiquity, but their numbers still grew. A form of Christianity made inroads among Arabs in Palestine, Yemen, and Arabia. In the fourth century the percentage of Christians was as high in the Sasanian Empire as in the Roman Empire. Even as the Huns, Ostrogoths, Visigoths, and Vandals caused havoc in the Roman Empire in the fourth and fifth centuries, many converted to Christianity. Syria was home to a vibrant Christianity. The gospel was first brought to Central Asia and China by Syriac-speaking missionaries.
Christian institutions in Asia or East Africa never developed the intellectual or sociopolitical influence that the European churches and Byzantium did. However, Armenia became the first state to adopt Christianity as its religion in 301. It was followed by others in the Caucasus, such as Albania, and Ethiopia and Eritrea in Africa. Christianity, a minority faith in Britain since the second century, began to be displaced by Anglo-Saxon paganism in the fifth century; this process began reversing after the Gregorian mission of 597. Missionaries also began to convert the Irish in the early fifth century.

### Heresies, schisms and councils

Regional Christianities produced diverse and sometimes competing churches. Ancient Christian authors identified any practice or doctrine which differed from apostolic tradition as heresy. The number of laws directed at heresy indicate it was a much higher priority than paganism for Christians of this period. For decades, Arianism embroiled the entire church, lay people who were not clergy and clergy alike, in arguing whether Jesus' divinity was equal to the Father's. The First Council of Nicaea in 325 attempted to resolve the controversy with the Nicene Creed. Along the Eastern Mediterranean where Christian factions struggled without accepting resolution, Christian communities were weakened, affecting their long-term survival.
Christian scriptures were formalized as the New Testament and distinguished from the Old Testament by the fourth century. Despite agreement on these texts, differences between East and West were becoming evident. The West was solidly Nicean while the East was largely Arian. The West condemned Roman culture as sinful and resisted state control, whereas the East harmonized with Greek culture and aimed for unanimity between church and state. The marriage of clerics was accepted in the East but forbidden in the West. The East advocated sharing the government of the church between five church leaders, arguing that the Patriarchs of Constantinople, Alexandria, Antioch, and Jerusalem were equal to the Pope. Rome asserted papal primacy.
Controversies over how Jesus' human and divine natures coexisted peaked when Nestorius declared Mary as the mother of Jesus' humanity, not his divinity, thereby giving Jesus two distinct natures. This led to a series of ecumenical councils: the Council of Ephesus was the church's third council, and it condemned Nestorius. Held in 431, the church in the Persian Empire refused to recognize its authority. In 451 the fourth council was the influential Council of Chalcedon; the Fifth was in 583, and the Sixth in 680–681. The seventh council of the church in 787, the Second Council of Nicaea, was the last one the Byzantine Church recognized as a general council.
While most of Christianity accepted the Chalcedonian Definition which emphasizes that the Son is a single person, the church in Persia rejected it and embraced Nestorianism instead. This led to the first separation between East and West in 482 when Oriental Orthodoxy formed in two general groups of Persians and Syrians. One group became the Church of the East (also known as the Assyrian, Nestorian, or Persian Church), while the majority of Christians in Syria and Mesopotamia became Syrian Orthodox (Jacobite). This cut off the flourishing school of Syrian Semitic Christian theologians and writers from the rest of Christendom. The Church of the East lay almost entirely outside the Byzantine Empire. It became the principal Church in Asia in the Middle Ages.

## Early Middle Ages (c. 600–1000)

By the early 600s, Christianity had spread around the Mediterranean. However, between 632 and 750, the Islamic caliphates conquered the Middle East, North Africa and the Iberian Peninsula. Muslim rule devastated Asian churches in the cities, but between the fifth and the eighth centuries Christianity had also been adopted in remote areas better enabling their survival. In the same period, war on multiple fronts turned the Eastern Roman Empire into the Byzantine Empire. Until the eighth century, Germanic Europe remained largely impoverished, politically fragmented and dependent on the church.
The Early Middle Ages was the formative period of Western "Christendom" which emerged at the end of this age. In and around this largely Christian world, barbarian invasion, deportation, and neglect produced large "unchurched" populations for whom Christianity was one religion among many that could be fused with aspects of local paganism. The church of this age was only indirectly influenced by the Bible.

### Monasticism and art

Until the end of the Early Middle Ages, Western culture was preserved and passed on primarily by monks known as "regular clergy" because they followed a regula: a rule. The rule included chastity, obedience and poverty sought through prayer, memorization of scripture, celibacy, fasting, manual labour, and almsgiving.
Monasteries served as orphanages and inns for travelers, and provided food for those in need. They supported literacy, practiced classical arts and crafts, and copied and preserved ancient texts in their scriptoria and libraries. Dedicated monks created illuminated manuscripts. From the sixth to the eighth centuries, most schools were connected to monasteries, but methods of teaching an illiterate populace could also include mystery plays, vernacular sermons, saints' lives in epic form, and artwork.
The early Middle Ages was an age of uncertainty, and the role of relics and "holy men" able to provide "special access" to the divine became increasingly important. Donations for the dead to receive prayers (with that special access) provided an ongoing source of wealth. Monasteries became increasingly organized, gradually establishing their own authority as separate from political and familial authorities, thereby revolutionizing social history. Medical practice was highly important, and medieval monasteries were best known for their public hospitals, hospices and their contributions to medicine. The sixth-century Rule of Saint Benedict has had extensive influence.
The East developed an approach to sacred art unknown in the West, adapting ancient portraiture in icons as intercessors between God and humankind. In the 720s, the Byzantine Emperor Leo banned the pictorial representation of Christ, saints, and biblical scenes, and destroyed much early representational art. The West condemned Leo's iconoclasm. By the tenth and early eleventh centuries, Byzantine culture began to recover its artistic heritage.

### Regional differences

Eastern Europe had been exposed to Christianity during Roman rule. Still, it was Byzantine Christianity, brought by the ninth-century saints Cyril and Methodius, that spurred the formation of its modern states. The brothers developed the Glagolitic alphabet to translate the Bible into the local language. Their disciples then developed the Cyrillic script which became the cultural and religious foundation for all Slavic nations.
In 635, the Church of the East brought Christianity to the Chinese Emperor whose decree to license the Christian faith was copied onto the Sianfu stele. It spread into northwestern China, Khotan, Turfan, and south of Lake Balkash in southeastern Kazakhstan, but its growth was halted in 845 by Emperor Wu-Tsung, who favoured Taoism. The Church of the East evangelized all along the Silk Road and was instrumental in converting some of the Mongol/Turkic peoples. After 700, when much of Christianity was declining, there were flourishing Christian societies along all the main trade routes of Asia, South India, the Nubian kingdoms, Ethiopia, and in Caucasian Armenia and Georgia.
In Western Europe, canon law was instrumental in developing key norms concerning oaths of loyalty, homage, and fidelity. These norms were incorporated into civil law, where traces remain. Within the tenets of feudalism, the church created a new model of consecrated kingship unknown in the East, and in 800, Clovis' descendant Charlemagne became its recipient when Pope Leo III crowned him emperor. Charlemagne engaged in a number of reforms which began the Carolingian Renaissance, a period of intellectual and cultural revival. His crowning set the precedent that only a pope could crown a Western emperor enabling popes to claim emperors derived their power from God through them. The Papacy became free from Byzantine control, and the former lands of the Exarchate became States of the church. However, the papacy was still in need of aid and protection, so the Holy Roman emperors often used that need to attempt domination of the Papacy and the Papal States. In Rome, the papacy came under the control of the city's aristocracy.
In Russia, the baptism of Vladimir of Kiev in 989 is traditionally associated with the conversion of the Kievan Rus'. Their new religious structure included dukes maintaining control of a financially-dependent church. Monasticism was the dominant form of piety for both peasants and elites who identified themselves as Christian while retaining many pre-Christian practices.
Viking raids in the ninth and tenth centuries destroyed many churches and monasteries, inadvertently leading to reform. Patrons competed in rebuilding so that "by the mid-eleventh century, a wealthy, unified, better-organized, better-educated, more spiritually sensitive Latin Church" resulted. There was another rise in papal power in the tenth century when William IX, Duke of Aquitaine, and other powerful lay founders of monasteries, placed their institutions under the protection of the papacy.

## High Middle Ages (c. 1000–1300)

Membership in the Christendom of this age began with baptism at birth. Every follower was supposed to have some knowledge of the Apostles' Creed and the Lord's Prayer, to rest on Sunday and feast days, attend mass, fast at specified times, take communion at Easter, pay various fees for the needy, and receive last rites at death.
The medieval papacy gained authority in every domain of European life as it gradually came to resemble the monarchies of its day. Canon law became a huge, highly complex, system of laws that omitted Christianity's earlier principles of inclusivity.
The High Middle Ages saw the formation of several fundamental Christian doctrines, such as the seven sacraments, the just reward for labour, "the terms of Christian marriage, the nature of clerical celibacy and the appropriate lifestyle for priests". Heresy was defined with new precision. Purgatory became an official doctrine. In 1215, confession became required for all. The rosary was created after veneration of Mary, mother of Jesus became a central aspect of the period.
Beginning at Cluny Abbey (910), which used Romanesque architecture to convey a sense of awe and wonder and inspire obedience, monasteries gained influence through the Cluniac Reforms. However, their cultural and religious dominance began to decline in the mid-eleventh century when secular clergy, who were not members of religious orders, rose in influence. Monastery schools lost influence as cathedral schools spread, independent schools arose, and universities formed as self-governing corporations chartered by popes and kings. Canon and civil law became professionalized, and a new literate elite formed, further displacing monks. Throughout this period, the clergy and the laity became "more literate, more worldly, and more self-assertive".

### Centralization

The Gregorian Reform under Pope Gregory VII (1073–1085) began "a new period in church history". Previously, the power of kings and emperors had been at least partly founded on connection to the sacred. Gregorian Reform intended to divest Western rulership of its sacramental character, and to establish the preeminence of the church by freeing it from state control. This shift reinforced the popes' temporal power, enabling a reorganization of the administration of the Papal States which brought a substantial increase in wealth. This enabled popes to become patrons in their own right, consolidate territory, centralize authority, and establish a bureaucracy.
State administrations were also centralizing, and competition between church and state, who claimed legal and tax jurisdiction over the same populace, created conflicts. A major example was the Investiture Controversy in the Holy Roman Empire, a conflict between the Holy Roman Emperor Henry IV and Pope Gregory VII over the secular appointment of bishops and abbots and control of their revenues. For the church, ending lay investiture would support independence from the state, encourage reform, and provide better pastoral care. For the kings, who could better control the powers and revenues of appointed bishops than those of hereditary noblemen, ending lay investiture meant the power of the Holy Roman Emperor and the European nobility would be reduced.
The Dictatus Papae of 1075 declared the pope alone could invest bishops. Disobedience to the Pope became equated with heresy; when Henry IV rejected the decree, he was excommunicated, which contributed to a civil war. A similar controversy occurred in England.

### Schism, crusade, spread, and retraction

The second separation of East and West took place in 1054 when the Eastern Church formed Byzantine Eastern Orthodoxy, which thereafter remained in communion with the Ecumenical Patriarchate of Constantinople, not the Pope. The Oriental Orthodox Church (the Church of the East), which had separated after Chalcedon, had survived against the odds with help from Byzantium. At the height of its expansion in the thirteenth century, the Church of the East stretched from Syria to eastern China and from Siberia to southern India and southern Asia.
Along with geographical separation, there had long been many cultural differences, geopolitical disagreements, and a lack of respect between east and west. Nevertheless, the Byzantine emperor Alexios I Komnenos still asked Pope Urban II for help with the Seljuk Turks in 1081, and Urban appealed in 1095 to European Christians to "go to the aid of their brethren in the Holy Land".
Urban's message had great popular appeal and resulted in the First Crusade. Drawing on powerful and prevalent aspects of folk religion, crusading connected pilgrimage, charity, and remission of sin with a willingness to fight. It gave ordinary Christians a tangible means of expressing brotherhood with the East and carried a sense of historical responsibility. The Crusades contributed to the development of national identities in European nations and increased division with the East. The evolving cult of chivalry of the Christian knight became a social and cultural influence before its decline during the 1400s. One significant effect of the Crusades was the invention of the indulgence.
Christianity was disappearing in Mesopotamia and inner Iran, although some Christian communities continued to exist further to the east. As churches in Egypt, Syria, and Iraq became subject to fervently Islamic militaristic regimes Christians were designated as dhimma, a status that guaranteed their protection but enforced their legal inferiority. Different communities adopted various survival strategies: some withdrew from interaction, others converted to Islam, and others sought outside help.
The Christianization of Scandinavia occurred in two stages: first, in the ninth century, missionaries operated without secular support; then a secular ruler would begin to oversee Christianization in their territory until an organized ecclesiastical network was established. By 1350, Scandinavia was an integral part of Western Christendom.

### Renaissance, science and technology

The Christian wars of reconquest, which lasted 200 years, had begun in Italy in 915 and in Spain in 1009 to retake territory lost to Muslims, causing fleeing Muslims in Sicily and Spain to leave behind their libraries. Between 1150 and 1200, monks searched them and found the works of Aristotle, Euclid and other ancient writers. The rediscovery of the complete works of Aristotle led to the Renaissance of the twelfth century. It also created conflict between faith and reason, resolved by a revolution in thought called scholasticism. The scholastic writings of Thomas Aquinas provided the foundation for much modern theology, philosophy and law. The renaissance revived the scientific study of natural phenomena which led to the scientific revolution in the West. There was no parallel renaissance in the East.
Byzantine art exerted a powerful influence on Western art in the twelfth and thirteenth centuries. Gothic architecture, intended to inspire contemplation of the divine, began in the same centuries. The Cistercian movement was a wave of monastic reform after 1098; Cistercians became instrumental in technological advancement in medieval Europe.

### Challenges and repression

The twelfth century saw a change in the ideal of a monk, from one of contemplative devotion to one of active reform. Among these new and often charismatic preachers was Saint Dominic who founded the Dominican Order and was significant in opposing Catharism. A military campaign conducted by papal and French forces to eliminate the Cathar heresy began in 1209, and continued until 1229, while Catharism itself lasted until 1350.
Moral misbehaviour and heresy, committed by either laity or clergy, were prosecuted in inquisitorial courts composed of both church and civil authorities that were established only when needed. Though these courts had no joint leadership nor joint organization, the Dominican Order held the primary responsibility for conducting inquisitions. The Medieval Inquisition brought between 8,000 and 40,000 people to interrogation and sentencing; death sentences were relatively rare. The penalty imposed most often was an act of penance which might include public confession. Bishops were the lead inquisitors, but they did not possess absolute power, nor were they universally supported. Inquisition became stridently contested as public opposition grew and riots against the Dominicans occurred. The Fourth Lateran Council of 1215 empowered inquisitors to search out moral and religious "crimes" even when there was no accuser. In theory, this granted them extraordinary powers. In practice, without sufficient local secular support, their task became so overwhelmingly difficult that inquisitors were endangered and some were murdered.
A turning point in Jewish-Christian relations occurred when the Talmud was put "on trial" in 1239 by Pope Gregory IX because of contents that mocked the central figures of Christianity. Talmudic Judaism came to be seen as so different from biblical Judaism that old Augustinian obligations to leave the Jews alone no longer applied. A rhetoric with elaborate stories casting Jews as enemies accused of ritual murder, the blood libel, and desecration of the Christian eucharist host grew among ordinary folk. The spread of the Black Death led to attacks on Jewish communities throughout the Holy Roman Empire by people who blamed them for the epidemic. Jews often acted as financial agents for the nobility, providing them loans with interest while being exempt from certain financial obligations. This attracted jealousy and resentment. Count Emicho of Leiningen massacred Jews in search of supplies and protection money, while the York massacre of 1190 also appears to have originated in a conspiracy by local leaders to liquidate their debts.
The nobility of Eastern Europe prioritized subduing the Balts, the last major polytheistic population in Europe, over crusading in the Holy Land. In 1147, the Divina dispensatione gave these nobles indulgences for the first of the Northern Crusades, which intermittently continued, with and without papal support, until 1316. The clergy pragmatically accepted the forced conversions the nobles perpetrated despite continued theological emphasis on voluntary conversion.

## Renaissance and Reformation (c. 1300–1650)
### Division in the West

The many calamities of the "long fourteenth century" – plague, famine, wars, and social unrest – led European people to believe the end of the world was imminent. This belief ran throughout society and became intertwined with anticlerical and anti-papal sentiments. Criticism of the church became an integral part of late medieval European life, and was expressed in both secular and religious writings, and movements of heresy or internal reform, although most attempts at reform between 1300 and 1500 failed.
In 1309, Pope Clement V fled Rome's factional politics by moving to Avignon in southern France. This Avignon Papacy, consisting of seven successive popes, unintentionally diminished papal prestige and power. Pope Gregory XI returned to Rome in 1377. After Gregory's death the following year, the papal conclave elected Urban VI to succeed him, but the French cardinals disapproved and elected Robert of Geneva instead. This began the Western Schism, during which there was more than one pope. In 1409, the Council of Pisa's attempted resolution resulted in the election of a third separate pope. The schism was finally resolved in 1417, with the election of Pope Martin V.
Throughout the Late Middle Ages, the church faced powerful challenges and vigorous political confrontations. The English scholastic philosopher John Wycliffe (1320–1384) urged the church to again embrace simplicity by giving up its property and wealth, to stop being subservient to secular politics, and to deny papal authority. Wycliffe's teachings were condemned as heresy, but he was allowed to live out the last two years of his life in his home parish. In 1382, Wycliffe created the first English translation of the Bible. Wycliffe's teachings influenced the Czech theologian Jan Hus (1369–1415) who also spoke out against what he saw as corruption in the church. Hus was convicted of heresy and burned at the stake. This was the impetus for the Bohemian Reformation and led to the Hussite Wars.
Meanwhile, a vernacular religious culture called the Devotio Moderna attempted to work toward a pious society of ordinary people. Through the Dutch scholar Desiderius Erasmus Roterodamus (1466–1536), Christian humanism grew and impacted literature and education. Between 1525 and 1534, William Tyndale used the Vulgate and Erasmus' Greek texts to create the Tyndale Bible. King James commissioned the King James Version in 1604, using all previous versions in Latin, Greek, and English as sources. It was published in 1611.

### The East and Renaissance

A 1452 reunion agreement between the Orthodox and Catholic churches was negated by the Fall of Constantinople to the Ottoman Empire in 1453, which sealed off Orthodoxy from the West for more than a century. Islamic law did not acknowledge the Byzantine church as an institution, but a concern for societal stability allowed it to survive. Financial handicaps, constant upheaval, simony, and corruption, impoverished many, and made conversion an attractive solution. This led to the state confiscating churches and turning them into mosques. The patriarchate became a part of the Ottoman system under Suleiman the Magnificent (1520–1566), and by the end of the sixteenth century, widespread desperation and low morale had produced crisis and decline. When Cyril I Loukaris (1572 – 1638) became Patriarch in 1620, he began leading the church toward renewal. A shared hostility towards Catholicism led Cyril to reach out to the Protestants of Europe and to be deeply impacted by their Reformation doctrines. Protestant pressure produced the Lukaris Confession.
The flight of Eastern Christians from Constantinople, and the manuscripts they carried with them, were important factors in stimulating literary renaissance in the West. The Catholic Church became a leading patron of art and architecture, commissioning many works and supporting renowned artists such as Michelangelo, Brunelleschi, Bramante, Raphael, Fra Angelico, Donatello, and Leonardo da Vinci. Although fifteenth-century popes struggled to reestablish papal authority, the Renaissance Papacy transformed Rome by rebuilding St. Peter's Basilica and establishing the city as a prestigious centre of learning. Reformation Protestants condemned these popes as corrupt for their lack of chastity, their nepotism, and the selling of "hats and indulgences".
In Russia, Ivan III of Russia adopted the style of the Byzantine imperial court to gain support among the Rus' elite who saw themselves as the new 'chosen' and Moscow as the New Jerusalem. Jeremias II (1536–1595), the first Orthodox patriarch to visit north-eastern Europe, founded the Orthodox Patriarchate of Russia during his journey.
The sixteenth-century success of Christianity in Japan was followed by one of the greatest persecutions in Christian history.

### Colonialism and missions

Colonialism, which began in the fifteenth century, originated either on a militaristic/political path, a commercial one, or with settlers who wanted land. Christian missionaries soon followed with their own separate agenda. "Companies, politicians, missionaries, settlers, and traders rarely acted together" and were often in conflict. Some missionaries supported colonialism while just as many took stances against colonial oppression. Between 1500 and 1800, Catholic Christianity gained followers worldwide through missionaries from the Spanish, Portuguese, and French empires.
Long before the first European colonists arrived, indigenous Christian communities, which were often in conflict with the newcomers, had existed in Asia and Africa. St.Thomas Christian communities in southern India existed continuously for more than 1000 years. In the 16th century, baptized Kongolese Christians were taken by Portuguese slavers to the Caribbean and Brazil where there are clear traces that they evangelized among their fellow sufferers. Former slaves returned to West Africa "with Bible in hand" before the arrival of European Protestant missionaries, founding Freetown, which would play a central role in the Christianization of West Africa.
During the Hispanic colonization of the Americas, the merging of native and Spanish traditions created a multitude of indigenous Christianities. In the seventeenth and eighteenth centuries, reductionist villages for natives in regions of Paraguay, Argentina and Brazil were established by Jesuits and other orders. Isolated from the rest of colonial society and forbidding serfdom and forced labor, Jesuits promoted local skills and technical innovations, working exclusively in the native language to form an "agrarian collective". The Spanish crown resented this autonomy, and the Jesuit order was banned; its members were expelled from Spain in 1767. Thereafter, reduction territories became open to settlers, and natives often became bondmen.

### Women, witch frenzy, expulsion and inquisition

Women in the Middle Ages were considered incapable of moral judgment and authority. However, there were women who became distinguished leaders of nunneries, exercising the same powers and privileges as their male counterparts, such as Hildegard of Bingen (d. 1179), Elisabeth of Schönau (d. 1164/65), and Marie d'Oignies (d. 1213). Although the Catholic Church had long ruled that witches did not exist, the conviction that witches were both real and malevolent developed throughout fifteenth-century European society. No single cause of "witch frenzy" is known, although the Little Ice Age is thought to have been a factor. Approximately 100,000 people, of whom 80% were women accused by those in their own villages, were prosecuted in mostly civil trials between 1561 and 1670; 40,000 to 50,000 were executed.
While the medieval church never officially repudiated Augustine's doctrine of protecting the Jews, defining them as heretical outsiders became increasingly common throughout society during the fifteenth century. Local rulers repeatedly evicted Jews from their lands and confiscated Jewish property.
Between 1478 and 1542, the Spanish and Portuguese inquisitions were initially authorized by the church but soon became state institutions. Authorized by Pope Sixtus IV in 1478, the Spanish Inquisition was established to combat fears that Jewish converts were conspiring with Muslims to sabotage the new state. Five years later a papal bull conceded control of the Spanish Inquisition to the Spanish crown making it the first national, unified, centralized institution of the nascent Spanish state. The Portuguese Inquisition, controlled by a state board of directors, incorporated anti-Judaism before the end of the fifteenth century and forced conversion led many Jewish converts to Portuguese colonies in India, where they suffered as targets of the Goa Inquisition. The bureaucratic and intellectual Roman Inquisition, best known for its condemnation of Galileo, served the papacy's political aims in Italy.

### Reformation

The Protestant Reformation is traditionally said to have begun when the Catholic monk Martin Luther nailed his Ninety-five Theses to the church door in Wittenberg in 1517. Luther's theses challenged the church's selling of indulgences, the authority of the Pope, and other church teachings, but the most basic question of the Reformation concerned the nature of the church's role in society and its authority. For Catholics, authority meant the Pope. For the protesters, authority was in the priesthood of believers and Scripture. Edicts of the Diet of Worms condemned Luther. After protracted and acrimonious struggle, three primary religious traditions emerged alongside Roman Catholicism: the Lutheran, the Reformed, and the Anglican traditions.
Luther wrote of two realms of government: the world, governed by secular authority, has the right to use force to maintain law and order, while the community of those who believe in salvation through grace and faith alone, renounce the use of force in all matters of faith, and are by nature self-governing. Neither realm can be allowed to dominate the other. Reformed theologian John Calvin also argued the church had the right to function without interference from the state, and established the ideal of a constitutional representative government. Puritans and other Dissenter groups in England, Huguenots in France, the “Beggars” in Holland, the Covenanters in Scotland who produced Presbyterianism, and the Pilgrim Fathers of New England all trace their theological roots to Calvinism. Presbyterianism is a form of church government that gives the laity half the power in church government, while Calvinism is its theology. Anglicanism was first created as the Church of England by Henry Tudor preserving catholic doctrine, establishing royal supremacy, and rejecting papal authority. At the same time, the Radical Reformation began in Germany and Switzerland.
The Roman Catholic Church responded in the Counter-Reformation, spearheaded by ten reforming popes between 1534 to 1605. The Council of Trent (1545–1563) denied each Protestant claim, and laid the foundation of modern Catholic policies. New monastic orders were formed, including the Society of Jesus – the "Jesuits" – who adopted military-style discipline and strict loyalty to the Pope.
Quarreling royal houses, already involved in dynastic disagreements, became polarized into the two religious camps. In 1562, France became the centre of a series of wars, of which the largest and most destructive was the Thirty Years' War (1618–1648). While some scholars argue that these wars were varieties of the just war tradition for liberty and freedom, most historians argue that the wars were more about nationalistic state-building and economics, and less about religion.

## Modern period (1650–1945)
### Ideological movements

The era of political absolutism followed the breakdown of Christian universalism in Europe. Abuses from absolutist Catholic kings gave rise to a virulent critique of Christianity that first emerged among the more extreme Protestant reformers in the 1680s as an aspect of the Age of Enlightenment. For 200 years, Protestants had been arguing for religious toleration, and by the 1690s, secular thinkers were rethinking the state's reasons for persecution, and they too began advocating for religious toleration. Concepts of freedom of religion, speech, and thought became established in the West.
Secularisation spread at every level of European society. Pioneered by Protestants, Biblical criticism advocated historicism and rationalism to make study of the Bible more scholarly and secular in the 1700s. In reaction to rationalism, Pietism, a holiness movement, began in Europe, spread to the Thirteen Colonies, and contributed to the First Great Awakening, a religious revival of the 1700s. Pietist Moravians, out of the Lutheran church, came to Georgia in 1732 where they influenced John Wesley, an Anglican missionary in Savannah. Wesley returned to England, and with his college friend George Whitfield, began preaching across England in open-air meetings, establishing dissenter churches that used innovative methods such as small accountability groups and prayer meetings, thereby beginning the Methodist church, which came back to the American colonies where it was, later, important on the American frontier. Dissenting Presbyterians and Baptists contributed to revival and to divisions over the movement, which turned political, and led to support for the American Revolution. In 1791, the new United States became the first Christian nation to mandate a separation of church and state; religious pluralism became the norm.
The rise of Protestantism contributed to human capital formation, the development of a new work ethic, economic growth, the European state system, and the development of modern capitalism in Northern Europe. However, urbanization and industrialisation created a plethora of new social problems. In Europe and North America, both Protestants and Catholics provided massive aid to the poor, supporting family welfare, and providing medicine and education.
The French Revolution led to a 1794 attempt by radical revolutionaries to violently de-Christianize France. As a result, the Eastern Orthodox Church rejected Enlightenment ideas as too dangerous to embrace.

### Nineteenth and twentieth centuries

American evangelicals preached a pietistic (holiness) type of Calvinism that culminated in the Second Great Awakening - a religious revival of the 1800s–1830s. Jonathan Edwards accented human choice and activism influencing evangelicalism thereafter. This revival produced Mormonism, Restorationism and the Holiness movement. Mormonism was a response to the fervent emotion of this revival. Mormons preached the restoration of first-century Christianity, upheld millenialism and premillenialism, religious utopianism, and responded to politics of the day. Restorationists, such as the Churches of Christ, Jehovah's Witnesses, and Seventh Day Adventists, also focused on restoring practices of the early church, emphasizing baptism as the crucial conversion experience, and biblical authority. The Holiness movement contributed to the development of Pentecostalism by combining Restorationism with the goal of sanctification defined as a deeper spiritual experience.
This revival focused on evidencing conversion through active moral reform: women's rights, temperance, literacy and the abolition of slavery. The process of reform established nationwide societies that businesses emulated leading to mergers that reshaped the nineteenth-century U.S. economy. The 300-year-old trans-Atlantic slave trade, in which some Christians had participated, had always garnered moral objections: by the eighteenth century, individual Quakers, Methodists, Presbyterians and Baptists began a written campaign against it. Congregations led by black preachers kept abolitionism alive into the early nineteenth century when some American Protestants organized the first anti-slavery societies. This ideological opposition eventually ended the trans-Atlantic slave trade, changing economic and human history on three continents.
The Third Great Awakening began in 1857 and took root throughout the world, especially in English-speaking countries. Nineteenth-century Protestant missionaries, many of them women, played a significant role in shaping nations and societies. Missionaries translated the Bible into local languages, generating in the process a written grammar, a lexicon of native traditions, and a dictionary of the local language. These were used to teach in missionary schools, resulting in the spread of literacy and indigenization. According to historian Lamin Sanneh, Protestant missionaries thus stimulated the "largest, most diverse and most vigorous movement of cultural renewal" in African history.
Liberal Christians embraced seventeenth-century rationalism, but its disregard of faith and ritual in maintaining Christianity led to its decline. Fundamentalist Christianity rose in the early 1900s as a reaction against modern rationalism. The Roman Catholic Church became increasingly centralized, conservative, and focused on loyalty to the Pope. By 1930, Protestant fundamentalism appeared to be dying. However, in the second half of the 1930s, Evangelicalism, which included a theology against liberalism based on a reevaluation of Reformation teachings, began uniting moderates of both sides.
In the early twentieth century, authoritarian European governments tended to establish state-supported churches. Such consanguinity would implicate the church in abuses of power. Nevertheless, Pope Pius XI declared that fascist governments had hidden "pagan intentions" and expressed the irreconcilability of the Catholic position with totalitarian fascist states which placed the nation above God. Most leaders and members of the largest Protestant church in Germany, the German Evangelical Church, supported the Nazi Party when they came to power in 1933. About a third of German Protestants formed the Confessing Church which opposed Nazism; its members were harassed, arrested, and otherwise targeted. In Poland, Catholic priests were arrested and Polish priests and nuns were executed en masse.

### Russian Orthodoxy

The Church reform of Peter I in the early 1700s had placed the Orthodox authorities under the control of the tsar who involved the church in various campaigns of russification which contributed to antisemitism. The communist revolutionaries who established the Soviet Union saw the Church as an enemy of the people and part of the tsarist state. The communist Soviet Union heavily persecuted the Russian Orthodox Church, executing up to 8,000 people by 1922. The League of Militant Atheists adopted a five-year plan in 1932 "aimed at the total eradication of religion by 1937". Despite this, the Orthodox Church continued to contribute to theology and culture.

## After World War II

Before 1945, about a third of the people in the world were Christians, and about 80% lived in Europe, Russia, and the Americas. After WWII ended, decolonization strengthened the emancipation efforts of Christian missionaries, leading to explosive growth in the churches of former colonies. With the collapse of communism, Christianity expanded in Eastern Europe, Russia, and in Africa and Asia where, by 2000, the percentage of Christians had increased to 32 percent of the world's Christians.
Christianity has had multiple regional "centers" since its beginnings, and these have produced different indigenous forms, initiatives, and expressions that have all contributed to its global expansion. In the first quarter of the twenty-first century, it is present in all six continents and a multitude of different cultures; most Christians live outside North America and Western Europe; white Christians are a global minority, and slightly over half of worldwide Christians are female. It is the world's largest religion with roughly 2.4 billion followers constituting around 31.2% of the world's population.
In 2000, approximately one-quarter of all Christians worldwide were part of Pentecostalism and its associated movements. By 2025, Pentecostals are expected to constitute one-third of the nearly three billion Christians worldwide making it the largest branch of Protestantism and the fastest-growing religious movement in worldwide Christianity.
The three main branches of Eastern Christianity are the Eastern Orthodox Church, the Oriental Orthodox Communion, and the Eastern Catholic Church. Roughly half of Eastern Orthodox Christians live in post-Eastern Bloc countries. Its oldest communities in Jerusalem, Antioch, Alexandria, Constantinople, and Georgia, are decreasing due to forced migration from religious persecution. Highly authoritarian and totalitarian governments have brought about crises and decline in many areas. The world's first Marxist super-power, and other communist governments, pursued anti-religious policies. In 2013, 17 Muslim majority states reported discrimination against religious minorities, including Christianity. Anti-Christian persecution has become a consistent human rights concern.
In the twentieth century, Christianity faced the challenges of secularism, and the changing moral climate concerning sexual ethics, gender, and exclusivity, leading to a decline in church attendance in the West. However, in the last quarter of the twentieth century around the world, religion left the private sphere and revitalized its public role, undermining theories of secularization. Hugh McLeod writes that political criticisms concerning power have had a wider impact.
Orthodox Christians in the East tend to be more conservative on most issues than Westerners. The Orthodox Church of the twenty-first century accepts Papal primacy but rejects the Papal supremacy that exerts external power and jurisdiction over the internal affairs of self-governing churches. In Orthodoxy, there is no position equivalent to the Roman Pope. Less than four-in-ten Orthodox favor reconciliation with the Roman Catholic Church. Unity between Protestants and Catholics also made little progress until 11 October 1962, when Pope John XXIII opened the Second Vatican Council. Roman Catholic ecumenical goals are to establish full communion amongst all the various Christian churches, however there is no agreement amongst evangelicals. The movement stalled, but there is a trend at the local level toward discussion, pulpit exchanges, and shared social action. In Hugh MacLeod's view, "A liberal Catholic is likely to have a lot in common with a liberal Methodist," and the influence of the internet will probably increase this.

### Theological revolution

For theologians writing after 1945, theology depended on the context of those applying it. The multiple wars of the twentieth century brought questions of theodicy to the forefront. For the first time since the pre-Constantinian era, Christian pacifism became an alternative to war. The Holocaust forced many to realize supersessionism can underlie hatred, ethnocentrism, and racism. Supersessionist texts are increasingly challenged in the twenty first century.
Liberation theology combined with the social gospel to redefine social justice and expose institutionalized sin to aid Latin American poor, but its context limited its application to other environments. Different historical and socio-political situations produced black theology and Feminist theology. Combining Christianity with questions of civil rights, aspects of the Black Power movement, and responses to black Muslims produced a black theology that spread to the United Kingdom, parts of Africa, and confronted apartheid in South Africa. The feminist movement of the mid-twentieth century began with an anti-Christian ethos but soon developed an influential feminist theology dedicated to transforming churches and society. Feminist theology developed at the local level as womanist theology of African-American women, the "mujerista" theology of Hispanic women, and Asian feminist theology.
In the mid to late 1990s, postcolonial theology emerged globally from multiple sources. It analyzes structures of power and ideology to recover what colonialism erased or suppressed in indigenous cultures. The missionary movement of the twenty-first century has transformed into a multi-cultural, multi-faceted global network of NGO's, short-term amateur volunteers, and traditional long-term bilingual, bicultural professionals who focus on evangelism and local development and not on 'civilizing' native people.