Christianity

Christianity
From Wikipedia, the free encyclopedia

Christianity is a monotheistic[1] religion centered on the life and teachings of Jesus of Nazareth as presented in the New Testament.[2] As of the early 21st century, it has between 1.5 billion[3][4] and 2.1 billion adherents,[5] representing about a quarter to a third of the world's population.[6] It is the state religion of at least fifteen countries.[7]
Its followers, known as Christians, believe that Jesus is[8] the Son of God and the Messiah (or Christ) prophesied in the Old Testament, the part of their scriptures they have in common with Judaism.[9] To Christians, Jesus Christ is a teacher, the model of a pious life, the revealer of God, and most importantly the saviour of humanity who suffered, died, and was resurrected in order to bring about salvation from sin.[10] Christians maintain that Jesus ascended into heaven and most denominations teach that Jesus will judge the living and the dead, granting everlasting life to his followers. Christians describe the New Testament account of Jesus' ministry as the Gospel, or "good news".
The Trinity is often regarded as an essential doctrine of mainstream Christianity. The common understanding of the Holy Trinity, espoused in the Nicene Creed, is one God who exists in three Persons – Father, the Son, and the Holy Spirit – who are coequal, co-eternal, of the same substance. "Father, Son and Holy Spirit" represents both the immanence and transcendence of God. God is believed to be infinite and God's presence may be perceived through the actions of Jesus and the Holy Spirit.[11]
The disciples were first called Christians (Greek Χριστιανός), meaning "followers of Christ", in Antioch.[12] Ignatius of Antioch was the first Christian to use the label in self-reference. The earliest recorded use of the term Christianity (Greek Χριστιανισμός) was also by Ignatius of Antioch, around AD 100.[13]
Like Judaism and Islam, Christianity is classified as an Abrahamic religion (see also Judeo-Christian).[14][15][16] Through missionary work and colonisation, Christianity spread firstly in the Middle East, North Africa, Europe and parts of India and subsequently throughout the entire world.[17]
In spite of important differences of interpretation and opinion, Christians share a set of beliefs that they hold as essential to their faith.[18]



Jesus Christ

The focus of a Christian's life is a firm belief in Jesus as the Son of God and the "Messiah" or "Christ". The title "Messiah" comes from the Hebrew word מָשִׁיחַ (māšiáħ) meaning anointed one. The Greek translation Χριστός (Christos) is the source of the English word "Christ".[19]
A depiction of Jesus and Mary, the Theotokos of Vladimir (12th century)
A depiction of Jesus and Mary, the Theotokos of Vladimir (12th century)
Christians believe that, as the Messiah, Jesus was anointed by God as ruler and savior of humanity, and hold that Jesus' coming was the fulfillment of messianic prophecies of the Old Testament. The Christian concept of the Messiah differs significantly from the contemporary Jewish concept. The core Christian belief is that, through the death and resurrection of Jesus, sinful humans can be reconciled to God and thereby are offered salvation and the promise of eternal life.[20]
While there have been theological disputes over the nature of Jesus, Christians generally believe that Jesus is God incarnate and "true God and true man" (or both fully divine and fully human). Jesus, having become fully human, suffered the pains and temptations of a mortal man, yet he did not sin. As fully God, he defeated death and rose to life again. According to the Bible, "God raised him from the dead,"[21] he ascended to heaven, is "seated at the right hand of the Father"[22] and will return again[23] to fulfil the rest of Messianic prophecy such as the Resurrection of the dead, the Last Judgment and final establishment of the Kingdom of God.
According to the Gospels of Matthew and Luke, Jesus was conceived by the Holy Spirit and born from the Virgin Mary. Little of Jesus' childhood is recorded in the canonical Gospels, however infancy Gospels were popular in antiquity. In comparison, his adulthood, especially the week before his death, are well documented in the Gospels contained within the New Testament.[neutrality disputed] The Biblical accounts of Jesus' ministry include: his baptism, miracles, preaching, teaching, and deeds.


Death and resurrection of Jesus
Christians consider the resurrection of Jesus to be the cornerstone of their faith and the most important event in human history.[24] Within the body of Christian beliefs, the death and resurrection of Jesus are two core events on which much of Christian doctrine and theology depend.[25][26] According to the New Testament, Jesus, the central figure of Christianity, was crucified, died, buried within a tomb, and resurrected three days later.[27] The New Testament mentions several resurrection appearances of Jesus on different occasions to his twelve apostles and disciples, including "more than five hundred brethren at once",[28] before Jesus' Ascension. Jesus's death and resurrection are the essential doctrines of the Christian faith, and are commemorated by Christians during Good Friday and Easter, particularly during the liturgical time of Holy Week. Arguments over death and resurrection claims occur at many religious debates and interfaith dialogues.[29]
As Paul the Apostle, an early Christian convert, wrote, "If Christ was not raised, then all our preaching is useless, and your trust in God is useless".[30][31] The death and resurrection of Jesus are the most important events in Christian Theology, as they form the point in scripture where Jesus gives his ultimate demonstration that he has power over life and death and thus the ability to give people eternal life.[32]
Generally, Christian churches accept and teach the New Testament account of the resurrection of Jesus.[33][34] Some modern scholars use the belief of Jesus' followers in the resurrection as a point of departure for establishing the continuity of the historical Jesus and the proclamation of the early church.[35] Some liberal Christians do not accept a literal bodily resurrection,[36][37] seeing the story as richly symbolic and spiritually nourishing[clarify] myth.


Soteriology
Soteriology is the branch of Christian theology that deals with salvation through Jesus Christ.[38] Christians believe salvation is a gift by means of the unmerited grace of God. Christians believe that, through faith in Jesus, one can be saved from sin and eternal death. The crucifixion of Jesus is explained as an atoning sacrifice, which, in the words of the Gospel of John, "takes away the sins of the world." One's reception of salvation is related to justification.[39]
The operation and effects of grace are understood differently by different traditions. Roman Catholicism and Eastern Orthodoxy teach the necessity of the free will to cooperate with grace.[40] Reformed theology places distinctive emphasis on grace by teaching that individuals are completely incapable of self-redemption, but the grace of God overcomes even the unwilling heart.[41] Arminianism takes a synergistic approach while Lutheran doctrine teaches justification by grace alone through faith alone.[42]


Trinity
Trinitarians
The term trinitarian denotes those Christians who hold to a belief in the concept of Trinity. Trinity refers to the teaching that the one God comprises three distinct, eternally co-existing persons; the Father' (from whom the Son and Spirit proceed), the Son (incarnate in Jesus Christ), and the Holy Spirit. Together, these three persons are sometimes called the Godhead,[43][44][45] although there is no single term in use in Scripture to denote the unified Godhead.[46] In the words of the Athanasian Creed, an early statement of Christian belief, "the Father is God, the Son is God, and the Holy Spirit is God, and yet there are not three Gods but one God.".[47]
According to this doctrine, God is not divided in the sense that each person has a third of the whole; rather, each person is considered to be fully God (see Perichoresis). The distinction lies in their relations, the Father being unbegotten; the Son being eternal yet begotten of the Father; and the Holy Spirit 'proceeding' from Father and (in Western theology) from the Son.[48] Regardless of this apparent difference in their origins, the three 'persons' are each eternal and omnipotent. This is thought by Trinitarian Christians to be the revelation regarding God's nature which Jesus Christ came to deliver to the world, and is the foundation of their belief system.
The word trias, from which trinity is derived, is first seen in the works of Theophilus of Antioch. He wrote of "the Trinity of God (the Father), His Word (the Son) and His Wisdom (Holy Spirit)".[49] The term may have been in use before this time. Afterwards it appears in Tertullian.[50][51] In the following century the word was in general use. It is found in many passages of Origen.[52]


Non-trinitarians
Nontrinitarianism includes all Christian beliefs systems that reject the Trinity, the doctrine that God is three distinct persons in one being. Various nontrinitarian views, such as adoptionism and Arianism, existed before the Trinity was formally defined as doctrine in AD 325.[53] Nontrinitarianism later appeared again in the Gnosticism of the Cathars in the 11th through 13th centuries, in the Age of Enlightenment of the 18th century, and in Restorationism during the 19th century. The nontrinitarian view was rejected by many early Christian bishops such as Irenaeus and subsequently by the Ecumenical Councils.[54] During the Reformation some nontrinitarians rejected these councils as spiritually tainted,[55] though most Christians continued to accept the value of many of the councils.
Casper Schwenckfeld and Melchior Hoffman advanced the view that Christ was only divine and not human.[56][57] Michael Servetus denied that the traditional doctrine of the Trinity was necessary to defend the divinity of Christ. He claimed that Jesus was God Himself in the flesh.[58] Modalists, such as Oneness Pentecostals, regard God as a single person, with the Father, Son, and Holy Spirit considered modes or roles by which the unipersonal God expresses himself,[59] in this way they parallel ancient Sabellians.[60][61] Latter-day Saints (commonly called Mormons) accept the divinity of the Father, Son, and Holy Spirit, but deny that they are the same being. Rather, they believe them to be separate beings united perfectly in will and purpose, thus making up one single Godhead. They believe that the Father, like the Son, has a glorified physical body.[62]


Scriptures
Christianity regards the Bible, a collection of canonical books in two parts (the Old Testament and the New Testament), as authoritative. It is believed by Christians to have been written by human authors under the inspiration of the Holy Spirit, and therefore for many it is held to be the inerrant Word of God.[63][64][65] Protestant Christians believe that the Bible contains all revealed truth necessary for salvation. This concept is known as Sola scriptura.[66] The books that are considered canon in the Bible vary depending upon the denomination using or defining it. These variations are a reflection of the range of traditions and councils that have convened on the subject. The Bible always includes books of the Jewish scriptures, the Tanakh, and includes additional books and reorganizes them into two parts: the books of the Old Testament primarily sourced from the Tanakh (with some variations), and the 27 books of the New Testament containing books originally written primarily in Greek[67]. The Roman Catholic and Orthodox canons include other books from the Septuagint Greek Jewish canon which Roman Catholics call Deuterocanonical.[68] Protestants consider these books apocryphal. Some versions of the Christian Bible have a separate Apocrypha section for the books not considered canonical by the publisher[69] .

Interpretation
Though Christians largely agree on the content of the Bible, there is significant divergence in its interpretation, or exegesis. In antiquity, two schools of exegesis developed in Alexandria and Antioch. Alexandrine interpretation, exemplified by Origen, tended to read Scripture allegorically, while Antiochene interpretation adhered to the literal sense, holding that other meanings (called theoria) could only be accepted if based on the literal meaning.[70]
Roman Catholic
Roman Catholic theology distinguishes two senses of scripture: the literal and the spiritual.[71]
The literal sense of understanding scripture is the meaning conveyed by the words of Scripture and discovered by exegesis, following the rules of sound interpretation. It has three subdivisions: the allegorical, moral, and anagogical (meaning mystical or spiritual) senses.
* The allegorical sense includes typology. An example would be the parting of the Red Sea being understood as a "type" (sign) of baptism.[72]
* The moral sense understands the scripture to contain some ethical teaching.
* The anagogical interpretation includes eschatology and applies to eternity and the consummation of the world.
Roman Catholic theology adds other rules of interpretation which include:
* the injunction that all other senses of sacred scripture are based on the literal;[73]
* that the historicity of the Gospels must be absolutely and constantly held;[74]
* that scripture must be read within the "living Tradition of the whole Church";[75] and
* that "the task of interpretation has been entrusted to the bishops in communion with the successor of Peter, the Bishop of Rome".[76]

Protestant
Many Protestants stress the literal sense or historical-grammatical method,[77] some even to the extent of rejecting other senses altogether. Other Protestant interpreters make use of typology.[78] Protestants characteristically believe that ordinary believers may reach an adequate understanding of Scripture because Scripture itself is clear (or "perspicuous"), because of the help of the Holy Spirit, or both. Martin Luther believed that without God's help Scripture would be "enveloped in darkness."[79] He advocated "one definite and simple understanding of Scripture."[79] John Calvin wrote, "all who...follow the Holy Spirit as their guide, find in the Scripture a clear light."[80] The Second Helvetic (Latin for "Swiss")[81] Confession, composed by the pastor of the Reformed church in Zurich (successor to Protestant reformer Zwingli) was adopted as a declaration of doctrine by most European Reformed churches.[82] The Confession contains this statement about interpreting Scripture:
"We hold that interpretation of the Scripture to be orthodox and genuine which is gleaned from the Scriptures themselves (from the nature of the language in which they were written, likewise according to the circumstances in which they were set down, and expounded in the light of like and unlike passages and of many and clearer passages)." The writings of the Church Fathers, and decisions of Ecumenical Councils, though "not despise[d]," were not authoritative and could be rejected.
– Second Helvetic Confession (1566)

Creeds
Creeds (from Latin credo meaning "I believe") are concise doctrinal statements or confessions, usually of religious beliefs. They began as baptismal formulas and were later expanded during the Christological controversies of the fourth and fifth centuries to become statements of faith.
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Apostles Creed
The Apostles Creed (Symbolum Apostolorum) was developed between the second and ninth centuries. It is the most popular creed used in worship by Western Christians. Its central doctrines are those of the Trinity and God the Creator. Each of the doctrines found in this creed can be traced to statements current in the apostolic period. The creed was apparently used as a summary of Christian doctrine for baptismal candidates in the churches of Rome.[83]
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Nicene Creed
The Nicene Creed, largely a response to Arianism, was formulated at the Councils of Nicaea and Constantinople in 325 and 381 respectively,[84] and ratified as the universal creed of Christendom by the Council of Ephesus in 431.[85]
The Chalcedonian Creed, developed at the Council of Chalcedon in 451,[86] though not accepted by the Oriental Orthodox Churches,[87] taught Christ "to be acknowledged in two natures, inconfusedly, unchangeably, indivisibly, inseparably": one divine and one human, and that both natures are perfect but are nevertheless perfectly united into one person.[88]
The Athanasian Creed, received in the western Church as having the same status as the Nicene and Chalcedonian, says: "We worship one God in Trinity, and Trinity in Unity; neither confounding the Persons nor dividing the Substance."[89]
Most Catholics, Protestants, and Orthodox accept the creeds.[90] Restorationists oppose the use of creeds.[91]

Afterlife and Eschaton
Most Christians believe that upon bodily death the soul experiences the particular judgment and is either rewarded with eternal heaven or condemned to an eternal hell. The elect are called "saints" (Latin sanctus: "holy") and the process of being made holy is called sanctification. In Catholicism, those who die in a state of grace but with either unforgiven venial sins or incomplete penance, undergo purification in purgatory to achieve the holiness necessary for entrance into heaven. At the second coming of Christ at the end of time, all who have died will be resurrected bodily from the dead for the Last Judgement, whereupon Jesus will fully establish the Kingdom of God in fulfillment of scriptural prophecies.[92][93]
Some groups do not distinguish a particular judgment from the general judgment at the end of time, teaching instead that souls remain in stasis until this time.[94] These groups, and others that do not believe in the intercession of saints, generally do not employ the word "saint" to describe those in heaven.
Universal Reconciliation is the view that all will eventually experience salvation, rejecting the concept that hell is literally everlasting.[95][96] Christians espousing this view are known as Universalists, not to be confused with Unitarian Universalists.[97]


Worship
Justin Martyr described 2nd century Christian liturgy in his First Apology (c. 150) to Emperor Antoninus Pius, and his description remains relevant to the basic structure of Christian liturgical worship:
"And on the day called Sunday, all who live in cities or in the country gather together to one place, and the memoirs of the apostles or the writings of the prophets are read, as long as time permits; then, when the reader has ceased, the president verbally instructs, and exhorts to the imitation of these good things. Then we all rise together and pray, and, as we before said, when our prayer is ended, bread and wine and water are brought, and the president in like manner offers prayers and thanksgivings, according to his ability, and the people assent, saying Amen; and there is a distribution to each, and a participation of that over which thanks have been given, and to those who are absent a portion is sent by the deacons. And they who are well to do, and willing, give what each thinks fit; and what is collected is deposited with the president, who succours the orphans and widows and those who, through sickness or any other cause, are in want, and those who are in bonds and the strangers sojourning among us, and in a word takes care of all who are in need."[98]
Thus, as Justin described, Christians assemble for communal worship on Sunday, the day of the resurrection, though other liturgical practices often occur outside this setting. Scripture readings are drawn from the Old and New Testaments, but especially the Gospels. Often these are arranged on an annual cycle, using a book called a lectionary. Instruction is given based on these readings, called a sermon, or homily. There are a variety of congregational prayers, including thanksgiving, confession, and intercession, which occur throughout the service and take a variety of forms including recited, responsive, silent, or sung. The Lord's Prayer, or Our Father, is regularly prayed. The Eucharist (called Holy Communion, or the Lord's Supper) is the part of liturgical worship that consists of a consecrated meal, usually bread and wine. Justin Martyr described the Eucharist:
" "And this food is called among us Eukaristia [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh."[98] "
Some Christian denominations view communion as indicating those who are already united in the church, restricting participation to their members not in a state of mortal sin (closed communion). Most other churches view communion as a means to unity, rather than an end, and invite all Christians or even anyone to participate (open communion). In some denominations, participation is decided by prior arrangement with a church leader.
Some groups depart from this traditional liturgical structure. A division is often made between "High" church services, characterized by greater solemnity and ritual, and "Low" services, but even within these two categories there is great diversity in forms of worship. Seventh-day Adventists meet on Saturday (the original Sabbath), while others do not meet on a weekly basis. Charismatic or Pentecostal congregations may spontaneously feel led by the Holy Spirit to action rather than follow a formal order of service, including spontaneous prayer. Quakers sit quietly until moved by the Holy Spirit to speak. Some Evangelical services resemble concerts with rock and pop music, dancing, and use of multimedia. For groups which do not recognize a priesthood distinct from ordinary believers the services are generally lead by a minister, preacher, or pastor. Still others may lack any formal leaders, either in principle or by local necessity. Some churches use only a cappella music, either on principle (e.g. many Churches of Christ object to the use of instruments in worship) or by tradition (as in Orthodoxy).
Worship can be varied for special events like baptisms or weddings in the service or significant feast days. In the early church Christians and those yet to complete initiation would separate for the Eucharistic part of the worship. In many churches today, adults and children will separate for all or some of the service to receive age-appropriate teaching. Such children's worship is often called Sunday school or Sabbath school (Sunday schools are often held before rather than during services).

Sacraments

In Christian belief and practice, a sacrament is a rite, instituted by Christ, that mediates grace, constituting a sacred mystery. The term is derived from the Latin word sacramentum, which was used to translate the Greek word for mystery.[99] Views concerning both what rites are sacramental, and what it means for an act to be a sacrament vary among Christian denominations and traditions.[99]
The most conventional functional definition of a sacrament is that it is an outward sign, instituted by Christ, that conveys an inward, spiritual grace through Christ. The two most widely accepted sacraments are Baptism and the Eucharist, however, the majority of Christians recognize seven Sacraments or Divine Mysteries: Baptism, Confirmation (Chrismation in the Orthodox tradition), and the Eucharist, Holy Orders, Reconciliation of a Penitent (confession), Anointing of the Sick, and Matrimony.[99] Taken together, these are the Seven Sacraments as recognised by churches in the High church tradition - notably Roman Catholic, Eastern Orthodox, Oriental Orthodox, Independent Catholic, Old Catholic and some Anglicans. Most other denominations and traditions typically affirm only Baptism and Eucharist as sacraments, while some Protestant groups, such as the Quakers, reject sacramental theology.[99] Some Christian denominations who believe these rites do not communicate grace prefer to call them ordinances.

Liturgical calendar

Roman Catholics, Anglicans, Eastern Christians, and traditional Protestant communities frame worship around a liturgical calendar. This includes holy days, such as solemnities which commemorate an event in the life of Jesus or the saints, periods of fasting such as Lent, and other pious events such as memoria or lesser festivals commemorating saints. Christian groups that do not follow a liturgical tradition often retain certain celebrations, such as Christmas, Easter and Pentecost. A few churches make no use of a liturgical calendar.[100]

Symbols

The cross, which is today one of the most widely recognised symbols in the world, was used as a Christian symbol from the earliest times.[101][102] In his book De Corona, written in the year 204, Tertullian tells how it was already a tradition for Christians to trace repeatedly on their foreheads the sign of the cross.[103] Although the cross was known to the early Christians, the crucifix did not appear in use until the fifth century.[104]
Among the symbols employed by the primitive Christians, that of the fish seems to have ranked first in importance. From monumental sources such as tombs it is known that the symbolic fish was familiar to Christians from the earliest times. The fish was depicted as a Christian symbol in the first decades of the second century.[105] Its popularity among Christians was due principally, it would seem, to the famous acrostic consisting of the initial letters of five Greek words forming the word for fish (Ichthys), which words briefly but clearly described the character of Christ and the claim to worship of believers: Iesous Christos Theou Yios Soter, meaning, Jesus Christ, Son of God, Saviour.[105]
Christians from the very beginning adorned their tombs with paintings of Christ, of the saints, of scenes from the Bible and allegorical groups. The catacombs are the cradle of all Christian art. The first Christians had no prejudice against images, pictures, or statues. The idea that they must have feared the danger of idolatry among their new converts is disproved in the simplest way by the pictures even statues, that remain from the first centuries.[106] Other major Christian symbols include the chi-rho monogram, the dove (symbolic of the Holy Spirit), the sacrificial lamb (symbolic of Christ's sacrifice), the vine (symbolising the necessary connectedness of the Christian with Christ) and many others. These all derive from writings found in the New Testament.[104]

History and origins

Early Church and Christological Councils
Christianity began as a Jewish sect.[107][108] The Christian Church traces its history to Jesus and the Twelve Apostles, and saw the early bishops of the Church as the successors of the Apostles in general. Central to the doctrines of the Roman Catholic, Orthodox and Anglican Churches is Apostolic Succession, the belief that the bishops are the spiritual successors of the original twelve apostles, through the historically unbroken chain of consecration.
From the beginning, Christians were subject to various persecutions. This involved even death for Christians such as Stephen[109] and James, son of Zebedee.[110] Larger-scale persecutions followed at the hands of the authorities of the Roman Empire, beginning with the year 64, when, as reported by the Roman historian Tacitus, the Emperor Nero blamed them for that year's great Fire of Rome. According to Church tradition, it was under Nero's persecution that early Church leaders Peter and Paul were each martyred in Rome. Further widespread persecutions of the Church occurred under nine subsequent Roman emperors including Domitian, Decius and Diocletian. From the year 150, Christian teachers began to produce theological and "apologetic" works aimed at defending the faith. These authors are known as the Church Fathers, and study of them is called Patristics. Notable early Fathers include Ignatius of Antioch, Polycarp, Justin Martyr, Irenaeus, Tertullian, Clement of Alexandria and Origen.
Christianity was legalized in the fourth century, when Constantine I issued the Edict of Milan in 313. Constantine was instrumental in the convocation of the First Council of Nicaea in 325, which sought to address the Arian heresy and formulated the Nicene Creed, which is still used by the Roman Catholic Church, Eastern Orthodoxy, Anglican Communion, and many Protestant churches.[90]
On 27 February 380, Emperor Theodosius I enacted a law establishing Catholic Christianity as the official religion of the Roman Empire.[111] This period of history was also marked by the inauguration of a series of Ecumenical (worldwide) Christological Councils which established and formally codified critical elements of the theology of the Church. In 382, the Council of Rome set the Canon of the Bible, listing the accepted books of the Old Testament and the New Testament. Also, the Council of Ephesus in 431 declared that Jesus existed both as fully Man and fully God simultaneously, clarifying his status in the Trinity. The meaning of the Nicene Creed was also declared a permanent doctrine of the Church.

Medieval period
In 452, Pope Leo the Great met Attila the Hun, and dissuaded him from sacking Rome.[112] However, in 476, the last Roman Emperor, Romulus Augustus was deposed.[112] Following the fall of the Roman Empire in the west, the church entered into a long period of missionary activity and expansion among the former barbarian tribes. Catholicism spread among the Germanic peoples (initially in competition with Arianism[113]), the Celts, the Slavic peoples; the Vikings and other Scandinavians; the Hungarians, the Baltic peoples and the Finns. The rise of Islam from 630 onwards, took the formerly Christian lands of the Levant, North Africa and much of Spain out of Christian control.[114] In 480, St. Benedict set out his Monastic Rule, establishing a system of regulations for the foundation and running of monasteries.[115] Monasticism became a powerful force throughout Europe,[113] and gave rise to many early centers of learning, most famously in Ireland, Scotland and Gaul, contributing to the Carolingian Renaissance of the 9th century.
The Middle Ages brought about major changes within the church. Pope Gregory the Great dramatically reformed ecclesiastical structure and administration.[116] In the early 8th century, iconoclasm became a divisive issue, when it was sponsored by the Byzantine emperors. The popes challenged imperial power and preserved the use of images outside the empire. The Second Ecumenical Council of Nicaea (787) finally pronounced in favour of icons.[117] In the early 10th century, western monasticism was further rejuvenated through the leadership of the great Benedictine monastery of Cluny.[118]

High Middle Ages
In the west, from the 11th century onward, older cathedral schools developed into universities (see University of Paris, University of Oxford, and University of Bologna.) Originally teaching only theology, these steadily added subjects including medicine, philosophy and law, becoming the direct ancestors of modern western institutions of learning.[119]
Accompanying the rise of the "new towns" throughout Western Europe, mendicant orders were founded, bringing the consecrated religious life out of the monastery and into the new urban setting. The two principal mendicant movements were the Franciscans[120] and the Dominicans[121] founded by St. Francis and St. Dominic respectively. Both orders made significant contributions to the development of the great universities of Europe. Another new order were the Cistercians, whose large isolated monasteries spearheaded the settlement of former wilderness areas. In this period church building and ecclesiastical architecture reached new heights, culminating in the orders of Romanesque and Gothic architecture and the building of the great European cathedrals.[122]
Pope Urban II at the Council of Clermont, where he preached the First Crusade.
Pope Urban II at the Council of Clermont, where he preached the First Crusade.
From 1095 under the pontificate of Urban II, the Crusades were launched.[123] These were a series of military campaigns in the Holy Land and elsewhere, initiated in response to pleas from the Byzantine Emperor Alexios I for aid against Turkish expansion. The Crusades ultimately failed to stifle Islamic aggression and even contributed to Christian enmity with the sacking and occupation of Constantinople during the Fourth Crusade.[124]
Beginning around 1184, following the crusades brought about by the Cathar heresy,[125] various institutions, broadly referred to as the Inquisition, were established with the aim of suppressing heresy and securing religious and doctrinal unity within Christianity through conversion and prosecution of alleged heretics.[126]

East-West Schism
Over a period stretching from the seventh to the fourteenth centuries, the Christian Church underwent a gradual schism that divided it into a Western (Latin) branch, now known as the Roman Catholic Church, and an Eastern (Greek) branch, which has become known as the Orthodox Church. These two churches disagree on a number of administrative, liturgical, and doctrinal issues, most notably papal primacy of jurisdiction.[127]
The Second Council of Lyon (1274) and the Council of Florence (1439) attempted to reunite the churches, but in both cases the Orthodox refused to ratify the decisions and the two principal churches remain in schism to the present day.

Protestant Reformation and Counter-Reformation

The 15th-century Renaissance brought about a renewed interest in ancient and classical learning, and a re-examination of accepted beliefs. The discovery of the Americas by Christopher Columbus in 1492 brought about a new wave of missionary activity as the church sought to spread the faith throughout the colonies. Another major schism, the Reformation, resulted in the splintering of the Western Christian Church into several Christian denominations.[128] On 31 October 1517 Martin Luther posted his 95 Theses, which protested the sale of indulgences and moved on to deny several key points of Roman Catholic doctrine. Others like Zwingli and Calvin further criticized Roman Catholic teaching and worship. These challenges developed into the movement called Protestantism, which repudiated the primacy of the pope, the role of tradition, the seven sacraments, and other doctrines and practices.[129] The Reformation in England accelerated in 1534,[130] when the English Parliament passed the Act of Supremacy making the King of England Supreme Head of the Church of England. Beginning in 1536, the monasteries throughout England, Wales, and Ireland were dissolved. Pope Paul III then excommunicated King Henry VIII in 1538, beginning what would become a decisive schism between Rome and Canterbury.[131]
The Counter-Reformation, or Catholic Reformation, is the name given to the response of the Roman Catholic Church to the challenge of Protestantism. The Council of Trent clarified and reasserted Roman Catholic doctrine. During the following centuries, competition between Roman Catholicism and Protestantism became deeply entangled with political struggles among European states.[132] Meanwhile, partly from missionary zeal, but under the impetus of colonial expansion by the European powers, Christianity spread to the Americas, Oceania, East Asia, and sub-Saharan Africa.
Throughout Europe, the divides caused by the Reformation led to outbreaks of religious violence, which was furthered by the establishment of separate state religions in various regions[citation needed]. Ultimately, these differences led to the outbreak of conflicts in which religion played a key factor. The Thirty Years' War, the English Civil War, and the French Wars of Religion are prominent examples. These events intensified the Christian debate on persecution and toleration, particularly in England.[133]

Christianity in the Modern Era

In the Modern Era, Christianity was confronted with various forms of skepticism and with certain modern political ideologies such as liberalism, nationalism and socialism. This included the anti-clericalism of the French Revolution, the Spanish Civil War, and general hostility of Marxist movements, especially the Russian Revolution.
Christian commitments in Europe dropped as modernity and secularism came into their own[clarify] in Western Europe, while religious commitments in America have been generally high in comparison to Western Europe. The late 20th Century has shown the shift of Christian adherents to the Third World and southern hemisphere in general, with Western Civilization no longer the chief standard bearer of Christianity.

Branches of Christianity in the present day

There is a diversity of doctrines and practices among groups calling themselves Christian. These groups are sometimes classified under denominations, though for theological reasons many groups reject this classification system.[134] Christianity may be broadly represented as being divided into four main groupings: Roman Catholicism, Eastern Orthodoxy, Oriental Orthodoxy, Protestantism and Restorationism[135][136]
Roman Catholicism and other Catholic groups
Roman Catholicism: The Roman Catholic Church, or "Catholic" church, includes the local churches, headed by bishops, in communion with the Pope, the Bishop of Rome. Like the Eastern Orthodox, the Roman Catholic Church claims to have existed since the foundation of Christianity through Apostolic succession. Grouped into 23 particular rites, it is the largest single body, with more than one billion baptized members.[137]
Various small communities, such as the Old Catholic and Independent Catholic Churches, include "Catholic" in their title, but are not in communion with the See of Rome. The Old Catholic church is in communion with the Anglican Communion, which considers itself a branch of the Catholic Church.

Eastern Orthodoxy
Eastern Orthodoxy: Those churches in communion with the Patriarchal Sees of the East, such as the Ecumenical Patriarch of Constantinople and others.[138] A number of conflicts with Western Christianity over questions of doctrine and authority culminated in the Great Schism. Like the Roman Catholic Church and the Anglican Communion, the Eastern Orthodox Church also claims a heritage from primeval Christianity and has an episcopal structure, though the autonomy of the individual, constituent churches is emphasized. It is the second largest single denomination in Christianity, with over 200 million adherents.[137]
Oriental Orthodoxy
Oriental Orthodoxy: Those Eastern Christian Churches that recognize only three ecumenical councils — the First Council of Nicaea, the First Council of Constantinople and the Council of Ephesus. They reject the dogmatic definitions of the Council of Chalcedon. Hence, these Churches are also called Old Oriental Churches or Non-chalcedonian churches.

Protestantism
In the 16th century, Martin Luther, Huldrych Zwingli, and John Calvin inaugurated what has come to be called Protestantism. Luther's primary theological heirs are known as Lutherans. Zwingli and Calvin's heirs are far broader denominationally, and are broadly referred to as the Reformed Tradition.[139] Most Protestant traditions branch out from the Reformed tradition in some way. In addition to the Lutheran and Reformed branches of the Reformation, there is Anglicanism after the English Reformation. The Anabaptist tradition was largely ostracized by the other Protestant parties at the time, but has achieved a measure of affirmation in more recent history.
The oldest Protestant groups separated from the Roman Catholic Church in the 16th century Protestant Reformation, followed in many cases by further divisions.[140] For example, the Methodist Church grew out of Anglican minister John Wesley's evangelical and revival movement in the Anglican Church.[141][142] Several Pentecostal and non-denominational Churches, which emphasize the cleansing power of the Holy Spirit, in turn grew out of the Methodist Church.[143][142] Because Methodists, Pentecostals, and other evangelicals stress "accepting Jesus as your personal Lord and Savior,"[144] which comes from John Wesley's emphasis of the New Birth,[145] they often refer to themselves as being born-again.[146][147]
Estimates of the total number of Protestants are very uncertain, partly because of the difficulty in determining which denominations should be placed in these categories, but it seems clear that Protestantism is the second largest major group of Christians after Roman Catholicism in number of followers (although the Eastern Orthodox Church is larger than any single Protestant denomination).[137]
Many members of the the Anglican Communion, a group of Anglican and Episcopal Churches that are descended from the Church of England, identify as both Protestant and Catholic.[148]
Some Christians who come out of the Protestant tradition identify themselves simply as "Christian", or "born-again Christian"; they typically distance themselves from the confessionalism and/or creedalism of other Christian communities[149] by calling themselves "non-denominational" – often founded by individual pastors, they have little affiliation with historic denominations.

Restorationism
Restorationism is composed of various unrelated Churches that believe they are restoring the "original version" of Christianity and not as "reforming" a Christian Church continuously existing from the time of Jesus.[150] They teach that the other three divisions of Christianity have introduced grave defects into Christianity, which is known as the Great Apostasy.[151][152] Some of these are historically connected to early-19th century Camp Meetings in the Midwest and Upstate New York. American Millennialism and Adventism, which arose from Evangelical Protestantism, produced the Jehovah's Witnesses movement (with 6.6 million members[153]), and, as a reaction specifically to William Miller, Seventh-day Adventists. Additionally, there are the following groups: Christadelphians, Churches of Christ with 2.6 million members, Disciples of Christ with 800,000 members,[154] and The Church of Jesus Christ of Latter-day Saints, the largest denomination of the Latter Day Saint movement with over 13 million members. Though Restorationists have some superficial similarities, their doctrine and practices vary significantly.
A simplified chart of historical developments of major groups within Christianity.
A simplified chart of historical developments of major groups within Christianity.
Mainstream Christianity is widely used to refer collectively to the common views of major denominations of Christianity (such as Roman Catholicism, Protestantism, Anglicanism, Orthodox Christianity) as against the particular tenets of other sects or Christian denomination. The context is dependent on the particular issues addressed, but usually contrasts the orthodox majority view against heterodox minority views of groups like Restorationists. In the most common sense, "mainstream" refers to Nicene Christianity, or rather the traditions which continue to claim adherence to the Nicene Creed.[155]

Ecumenism

Most churches have long expressed ideals of being reconciled with each other, and in the 20th century Christian ecumenism advanced in two ways.[156] One way was greater cooperation between groups, such as the Edinburgh Missionary Conference of Protestants in 1910, the Justice, Peace and Creation Commission of the World Council of Churches founded in 1948 by Protestant and Orthodox churches, and similar national councils like the National Council of Churches in Australia which includes Roman Catholics.[157]
The other way was institutional union with new United and uniting churches. Congregationalist, Methodist, and Presbyterian churches united in 1925 to form the United Church of Canada,[158] and in 1977 to form the Uniting Church in Australia. The Church of South India was formed in 1947 by the union of Anglican, Methodist, Congregationalist, Presbyterian, and Reformed churches.[159]
Steps towards reconciliation on a global level were taken in 1965 by the Roman Catholic and Orthodox churches mutually revoking the excommunications that marked their Great Schism in 1054;[160] the Anglican Roman Catholic International Commission (ARCIC) working towards full communion between those churches since 1970;[161] and the Lutheran and Roman Catholic churches signing The Joint Declaration on the Doctrine of Justification in 1999 to address conflicts at the root of the Protestant Reformation. In 2006 the Methodist church adopted the declaration.[162]

Figures
With an estimated number of adherents that ranges between 1.5 billion[163] and 2.1 billion,[163] split into around 34,000 separate denominations, Christianity is the world's largest religion.[164] The Christian share of the world's population has stood at around 33 per cent for the last hundred years. This masks a major shift in the demographics of Christianity; large increases in the developing world have been accompanied by substantial declines in the developed world, mainly in Europe and North America.[165] On current projections, by 2050 only about one-fifth of the world's Christians will be non-Hispanic whites.[166] It is still the predominant religion in Europe, the Americas, the Philippines, and Southern Africa.[167] However it is declining in some areas including Oceania (Australia and New Zealand), Northern Europe (including Great Britain,[168] Scandinavia and other places), France, Germany, the Canadian provinces of Ontario and Quebec, the Western and Northern portions of the United States, and parts of Asia (especially the Middle East[169][170][171], South Korea[172], Taiwan[173] and Macau[174]).
In most countries in the developed world, church attendance among people who continue to identify themselves as Christians has been falling over the last few decades.[175] Some sources view this simply as part of a drift away from traditional membership institutions,[176] while others link it to signs of a decline in belief in the importance of religion in general.[177]
Christianity, in one form or another, is the sole state religion of the following nations: Argentina (Roman Catholic),[178] Bolivia (Roman Catholic),[179] Costa Rica (Roman Catholic),[180] Cyprus (Orthodox),[181] Denmark (Evangelical Lutheran),[182] El Salvador (Roman Catholic),[183] England (Anglican),[184] Finland (Evangelical Lutheran & Orthodox),[185][186] Greece (Greek Orthodox),[183] Iceland (Evangelical Lutheran),[187] Liechtenstein (Roman Catholic),[188] Malta (Roman Catholic),[189] Monaco (Roman Catholic),[190] Norway (Evangelical Lutheran),[191] Scotland (Presbyterian),[192] Switzerland (Roman Catholic, Old Catholic, or Protestant - denomination varies per canton)[193] and Vatican City (Roman Catholic).[194]