In the5th century in Christianity, there were many developments which led to further fracturing of theState church of the Roman Empire. EmperorTheodosius II called twosynods inEphesus, one in 431 and one in 449, that addressed the teachings of Patriarch of ConstantinopleNestorius and similar teachings. Nestorius had taught that Christ's divine and human nature were distinct persons, and henceMary was the mother of Christ but not themother of God. The Council rejected Nestorius' view causing many churches, centered on theSchool of Edessa, to aNestorian break with the imperial church. Persecuted within the Roman Empire, many Nestorians fled toPersia and joined theSassanid Church (the futureChurch of the East) thereby making it a center ofNestorianism.^[1] By the end of the 5th century, the global Christian population was estimated at 10-11 million.^{[citation needed]} In 451 theCouncil of Chalcedon was held to clarify the issue further. The council ultimately stated that Christ's divine and human nature were separate but both part of a single entity, a viewpoint rejected by many churches who called themselvesmiaphysites. The resulting schism created a communion of churches, including the Armenian, Syrian, and Egyptian churches, that is today known asOriental Orthodoxy.^[2] In spite of these schisms, however, the imperial church still came to represent the majority of Christians within the Roman Empire.^[3]

At the end of the 4th century the Roman Empire had effectively split into two states although its economy and the Church were still strongly tied. The two halves of the empire had always had cultural differences, in particular exemplified by the widespread use of the Greek language in the Eastern Empire and the more limited use of Greek in the West (Greek was used in the West but Latin was displacing it as the spokenvernacular. By the 5th century scholars in the West had begun to abandon Greek in favor of the use of Latin. TheChurch in Rome, in particular, began to encourage the use of Latin in the western provinces and publishedJerome'sVulgate, the first authorized translation of the Bible in Latin.

At the same time as these changes were taking place the Western Empire was beginning todecay rapidly.Germanic tribes, particularly theGoths, gradually conquered the western provinces. The Arian Germanic tribes established their own systems of churches and bishops in the western provinces but were generally tolerant of those who chose to remain loyal to the imperial church.^[4]

TheCouncil of Ephesus in 431 and theCouncil of Chalcedon in 451 led to the schism withChurch of the East and the schism with theMiaphysite churches. The latter schism established what is today known asOriental Orthodoxy.

Theodosius II called a council to settle the Nestorian controversy. Nestorius,Patriarch of Constantinople, opposed use of the termTheotokos (Greek Η Θεοτόκος, "God-bearer").^[5] This term had long been used by orthodox writers, and it was gaining popularity along with devotion to Mary as Mother of God.^[5] He reportedly taught that there were two separate persons in the incarnate Christ, though whether he actually taught this is disputed.^[5]Cyril of Alexandria charged that this teaching of Nestorius implied that there had been in fact two Jesus Christs; one Christ was a man born of the virgin Mary and the other was divine and not born but also Jesus Christ.

Cyril of Alexandria regarded the embodiment of God in the person of Jesus Christ to be so mystically powerful that it spread out from the body of the God-man into the rest of the race, to reconstitute human nature into a graced and deified condition of the saints (Jesus Christ as the new Adam), one that promised immortality and transfiguration to believers. Nestorius, on the other hand, saw the incarnation as primarily a moral and ethical example to the faithful, to follow in the footsteps of Jesus. Cyril repeatedly stressed the simple idea that it was God who walked the streets of Nazareth (hence Mary wasTheotokos or Mother of God), and God who had appeared in a transfigured humanity (see thetheophany). Nestorius spoke of the distinct 'Jesus the Man' and 'the divine Logos' in ways that Cyril thought were toodichotomous, widening the ontological gap between man and God in a way that would annihilate the person (hypostasis) of Christ a position termeddyophysite.^[6]

The council deposed Nestorius, repudiatedNestorianism, proclaiming the VirginMary as the Theotokos.

After quoting theNicene Creed in its original form, as at the First Council of Nicaea, without the alterations and additions made at the First Council of Constantinople, it declared it "unlawful for any man to bring forward, or to write, or to compose a different (ἑτέραν) Faith as a rival to that established by the holy Fathers assembled with theHoly Ghost in Nicæa."^[7]

TheCouncil of Chalcedon took place from October 8 to November 1, 451, atChalcedon (a city ofBithynia inAsia Minor). It was the fourth of thefirst seven Ecumenical Councils and is therefore recognized asinfallible in itsdogmatic definitions by theRoman Catholic andEastern Orthodox churches.Chalcedon was called to address concerns first raised in November 448, at a synod at Constantinople, which condemnedEutyches for unorthodoxy. Anarchimandrite of a large Constinapolitan monastery,^[8] Eutyches taught a Christological position at the opposite extreme from that of Nestorius,^[9] namely that Christ was notconsubstantial with humanity.^[10] In order to settle the issue, theSecond Council of Ephesus was held in 449, at which Eutyches was exonerated and returned to his monastery.^[9] Although intended to be anecumenical council, this council was not called with enough notice for the Western bishops to attend, and was subsequently labeled a "robber council" by the Council of Chalcedon.

The Council of Chalcedon repudiated Eutyches and his doctrine ofmonophysitism, described and delineated the "Hypostatic Union" andtwo natures of Christ, human and divine. It also adopted theChalcedonian Creed, which describes the "full humanity and full divinity" ofJesus, the second person of theHoly Trinity.

Nestorian churches are Eastern Christian churches that keep the faith of only the first two ecumenical councils, i.e., theFirst Council of Nicaea and theFirst Council of Constantinople. "Nestorian" is an outsider's term for a tradition that predated the influence ofNestorius. Thus, "Assyrian Church of the East" is a more neutral term.TheNestorian Schism was the first major schism of the Eastern Churches and was addressed with the Council of Ephesus.

Eastern Orthodoxy strives to keep the faith of the sevenEcumenical Councils. In contrast, the term "Oriental Orthodoxy" refers to the churches ofEastern Christian traditions that keep the faith of only the first three ecumenical councils — theFirst Council of Nicaea, theFirst Council of Constantinople and the Council of Ephesus — and rejected thedogmatic definitions of the Council of Chalcedon. It is sometimes called the Greek Orthodox to distinguish it from the Coptic Orthodox Patriarchate of Alexandria. In Egypt, members of the Greek Orthodox Patriarchate were also calledMelkite, because they remained in communion with the Patriarch of Constantinople.

Oriental Orthodox is also sometimes referred to as "monophysites", "non-Chalcedonians", or "anti-Chalcedonians", although today the Oriental Orthodox Church denies that it is monophysite and prefers the term "miaphysite" to denote the "joined" nature of Jesus. Thedogma chosen by the Oriental Orthodox was interpreted to express that Jesus Christ had two natures (both human and divine) that were unified hypostatically into aone single nature. This was interpreted from the Byzantine position to be an argument that greatly diminished the human reality of Christ, by also making the human will of Christ one not offreewill.^[11][12]

Those who disagreed with the findings of the Council of Chalcedon are today known as theCoptic Orthodox Church of Alexandria. This included theEthiopian Orthodox Tewahedo Church and theArmenian Orthodox church. There was a similar split inSyria (Patriarchate of Antioch) into theGreek Orthodox Church of Antioch and theSyriac Orthodox Church.

Late Antique Christianity produced a great many renowned Fathers who wrote volumes of theological texts, includingAugustine,Gregory Nazianzus,Cyril of Jerusalem,Ambrose of Milan,Jerome, and others. What resulted was a golden age of literary and scholarly activity. Some of these fathers, such asJohn Chrysostom andAthanasius, suffered exile, persecution, or martyrdom from hereticalByzantine Emperors. Many of their writings are translated into English in the compilations ofNicene and Post-Nicene Fathers.

The Church Fathers, Early Church Fathers, or Fathers of the Church are the early and influentialtheologians and writers in the Christian Church, particularly those of the first five centuries of Christian history. The term is used of writers and teachers of the Church, not necessarilysaints. Teachers particularly are also known asdoctors of the Church, althoughAthanasius called themmen of little intellect.^[13]

Those who wrote inGreek are called the Greek (Church) Fathers. Famous Greek Fathers include:Irenaeus of Lyons,Clement of Alexandria, theheterodoxOrigen,Athanasius of Alexandria, John Chrysostom,Cyril of Alexandria and theCappadocian Fathers (Basil of Caesarea,Gregory Nazianzus,Peter of Sebaste andGregory of Nyssa.

The Cappadocians promoted early Christian theology and are highly respected in both Western and Eastern churches as saints. They were a 4th-centurymonastic family led bySaint Macrina the Younger to provide a central place for her brothers to study and meditate, and also to provide a peaceful shelter for their mother. Abbess Macrina fostered the education and development of three men who collectively became designated the Cappadocian Fathers:Basil the Great who was the second oldest of Macrina's brothers (the first being the famous Christian juristNaucratius) and eventually became a bishop;Gregory of Nyssa who also became a bishop of the diocese associated thereafter with his name; andPeter of Sebaste who was the youngest of Makrina's brothers and later became bishop of Sebaste.

These scholars along withGregory Nazianzus set out to demonstrate that Christians could hold their own in conversations with learned Greek-speaking intellectuals and that Christian faith, while it was against many of the ideas of Plato and Aristotle (and other Greek Philosophers), was an almost scientific and distinctive movement with the healing of the soul of man and his union with God at its center—one best represented by monasticism. They made major contributions to the definition of theTrinity finalized at theFirst Council of Constantinople in 381 and the final version of the Nicene Creed which was formulated there.

Subsequent to the First Council of Nicea, Arianism did not simply disappear. The semi-Arians taught that the Son is of like substance with the Father (homoiousios), as against the outright Arians who taught that the Son was unlike the Father (heterousian). So the Son was held to belike the Father but not of the same essence as the Father.The Cappadocians worked to bring these semi-Arians back to the Orthodox cause. In their writings they made extensive use of the formula "three substances (hypostases) in one essence (homoousia)," and thus explicitly acknowledged a distinction between the Father and the Son (a distinction that Nicea had been accused of blurring) but at the same time insisting on their essential unity.

Cyril of Alexandria was the Bishop of Alexandria when the city was at its height of influence and power within the Roman Empire. Cyril wrote extensively and was a leading protagonist in the Christological controversies of the later 4th, and 5th centuries. He was a central figure in the First Council of Ephesus. Cyril is counted among the Church Fathers and theDoctors of the Church, and his reputation within the Christian world has resulted in his titles "Pillar of Faith" and "Seal of all the Fathers".

John Chrysostom,archbishop of Constantinople, is known for his eloquence inpreaching andpublic speaking, his denunciation of abuse of authority by both ecclesiastical and political leaders, theDivine Liturgy of St. John Chrysostom, and hisascetic sensibilities. After his death (or according to some sources, during his life) he was given theGreek surnamechrysostomos, meaning "golden mouthed", rendered inEnglish as Chrysostom.^[14][15]

Chrysostom is known within Christianity chiefly as apreacher, theologian, andliturgist, particularly in theEastern Orthodox Church. Outside the Christian tradition Chrysostom is noted for eight of his sermons which played a considerable part in the history ofChristian antisemitism and were extensively misused by theNazis in their ideological campaign against the Jews.^[16][17]

Those fathers who wrote inLatin are called the Latin (Church) Fathers. These includeTertullian (who later in life converted toMontanism),Cyprian of Carthage,Gregory the Great,Augustine of Hippo,Ambrose of Milan, andJerome.

SaintJerome is best known as the translator of theBible fromGreek andHebrew intoLatin. He also was aChristian apologist. Jerome's edition of the Bible, theVulgate, is still an important text of the Roman Catholic Church. He is recognised by the Roman Catholic Church as aDoctor of the Church.

SaintAugustine, Bishop ofHippo Regius, was a philosopher and theologian. Augustine is one of the most important figures in the development ofWestern Christianity. Augustine was radically influenced by Platonism.^[18] He framed the concepts oforiginal sin andjust war as they are understood in the West. When Rome fell and the faith of many Christians was shaken, Augustine developed the concept of the Church as a spiritualCity of God, distinct from the material City of Man.^[19] Augustine's work defined the start of themedievalworldview, an outlook that was later firmly established byPope Gregory the Great.^[19]

Augustine was born in present-dayAlgeria to a Christian mother,Saint Monica. He was educated inNorth Africa and resisted his mother's pleas to become Christian. He took a concubine and became aManichean. He later converted to Christianity, became a bishop, and opposed heresies, such as the belief that people candeserve salvation by being good. His works—includingThe Confessions, which is often called the first Westernautobiography—are still read around the world. In addition he believed inpapal supremacy.^{[20][failed verification]}

By the 6th century, specifically underJustinian I, theecclesiastical had evolved ahierarchical "pentarchy" or system of five sees (later calledpatriarchates), with a settled order of precedence. Rome, as the ancient capital and once largest city of the empire, was given the presidency or primacy of honour within the pentarchy into whichChristendom was then divided; thoughOrthodox Christianity held and still holds that the patriarch of Rome is the "first among equals".Constantinople was second in precedence as thenew capital of the empire.

The council at Chalcedon granted its archbishop jurisdiction over the three provinces mentioned by theFirst Council of Constantinople. The council also ratified an agreement between Antioch and Jerusalem, whereby Jerusalem held jurisdiction over three provinces,^[21] numbering it among the five great sees.^[22]

The disagreements which led to theGreat Schism started to become evident as early as the 4th century. Although 1054 is the date usually given for the beginning of the Great Schism, there is, in fact, no specific date on which the schism occurred. What really happened was a complex chain of events whose climax culminated with the sacking of Constantinople by theFourth Crusade in 1204.

The events leading to schism were not exclusively theological in nature. Cultural, political, and linguistic differences were often mixed with the theological. Unlike theCoptic Orthodox Church of Alexandria orArmenian Apostolic Church who split in the 5th century, the eastern and western parts of the Church remained loyal to their faith and to the authority of the seven ecumenical councils. They were united, by virtue of their common faith and tradition, in "one Church", since they treated dissenting churches asheretical.

Some scholars^[23] have argued that the schism between East and West has very ancient roots and that sporadic schisms in the common unions took place, such as underPope Damasus I (4th and 5th century).

While the origins of papal primacy concept arehistorically obscure,Pope Leo I expressed a doctrine that the bishop of Rome was the legal heir ofSaint Peter and claimed that evenother ancient patriarchs should defer to Rome.

Monasticism is a form of asceticism whereby one renounces worldly pursuits (in contemptu mundi) and concentrates solely on heavenly and spiritual pursuits, especially by the virtueshumility, poverty, and chastity. It began early in the Church as a family of similar traditions, modeled upon Scriptural examples and ideals, and with roots in certain strands of Judaism.John the Baptist is seen as the archetypical monk, and monasticism was inspired by the organisation of the Apostolic community as recorded inActs of the Apostles. Central figures in the development of monasticism wereBasil of Caesarea in the East andBenedict of Nursia in the West, who created the famousBenedictine Rule, which became the most common rule throughout theMiddle Ages.

Many distinct monastic orders developed withinRoman Catholicism andAnglicanism.Benedictines, founded in 529 by Benedict atMonte Cassino, stresses manual labor in a self-subsistent monastery.

TheMigration Period, also calledBarbarian Invasions orVölkerwanderung (German for "wandering of the peoples"), was a period ofhuman migration which occurred roughly between 300 and 700 inEurope,^[24] marking the transition fromLate Antiquity to theEarly Middle Ages. These movements were catalyzed by profound changes within both the Roman Empire and the so-called 'barbarian frontier'. Migrating peoples during this period included theGoths,Vandals, IranianAlans, TurkicBulgars,Suebi,Frisians, andFranks, among otherGermanic,Iranian,Turkic andSlavic tribes.

TheSack of Rome by invading European Goths marks the beginning of theMiddle Ages, whereupon Rome and most parts ofWestern Europe became increasingly isolated and irrelevant to the churches in the eastern and southern Mediterranean. This was a situation which suited and pleased many of the patriarchs and bishops of those churches.^[25]

In the 4th century some Eastern Germanic tribes, notably the Goths, adoptedArianism. From the 6th century, Germanic tribes were converted (and re-converted) bymissionaries of the Roman Catholic Church, firstly among the Franks, afterClovis I's conversion to Catholicism in 496. In 498 (497 or 499 are also possible) he let himself be baptised inReims.^[26] With this act, the Frankish Kingdom became Christian, although it would take until the 7th century for the population to abandon some of their pagan customs.^[27] This was typical of the Christianization of Europe. Conversion of theWest andEast Germanic tribes took place "top to bottom", in the sense that missionaries aimed at converting Germanic nobility first, which would then impose their new faith on the general population

The first non-Roman area to adopt monasticism wasIreland, which developed a unique form closely linked to traditional clan relations, a system that later spread to other parts ofEurope, especiallyFrance. The earliest monastic settlements in Ireland emerged at the end of the 5th century. The first identifiable founder of a monastery wasSaint Brigit, a saint who ranked withSaint Patrick as a major figure of the Irish church. The monastery atKildare was a double monastery, with both men and women ruled by the Abbess, a pattern found in other monastic foundations.

Commonly Irish monasteries were established by grants of land to an abbot or abbess who came from a local noble family. The monastery became the spiritual focus of the tribe or kin group. Successive abbots and abbesses were members of the founder's family, a policy which kept the monastic lands under the jurisdiction of the family (and corresponded to Irish legal tradition, which only allowed the transfer of land within a family).

Ireland was a rural society of chieftains living in the countryside. There was no social place for urban leaders, such as bishops. In Irish monasteries the abbot (or abbess) was supreme, but in conformance to Christian tradition, bishops still had important sacramental roles to play (in the early Church the bishops were the ones who baptized new converts to bring them into the Church). In Ireland, the bishop frequently was subordinate to (or co-equal with) the abbot and sometimes resided in the monastery under the jurisdiction of the abbot.

Irish monasticism maintained the model of a monastic community while, likeJohn Cassian, marking the contemplative life of the hermit as the highest form of monasticism. Saints' lives frequently tell of monks (and abbots) departing some distance from the monastery to live in isolation from the community.

Irish monastic rules specify a stern life of prayer and discipline in which prayer, poverty, and obedience are the central themes. Yet Irish monks did not fearpagan learning. Irish monks needed to learn a foreign language, Latin, which was the language of the Church. Thus they read Latin texts, both spiritual and secular, with an enthusiasm that their contemporaries on the continent lacked. By the end of the 7th century, Irish monastic schools were attracting students fromEngland and from Europe.

The Franks and their rulingMerovingian dynasty that had migrated toGaul from the 3rd century had remained pagan at first. On Christmas 498,^[28] however,Clovis I following his victory at theBattle of Tolbiac converted to theorthodox faith of the Roman Church and let himself be baptised atRheims. The details of this event have been passed down byGregory of Tours.

Clovis I' wifeClotilde was Roman Catholic and had an important role in the conversion of her husband.^[29] Long before his baptism, Clovis had allowed his sons to be baptised.^[30] However, the decisive reason for Clovis to adopt the Christian belief was the spiritual battle aid he received fromChrist.^[31] In theBattle of Tolbiac he came in such difficulties that he prayed to Christ for victory. Clovis was victorious, and afterwards he had himself instructed in the Christian faith bySaint Remigius.^[32]

That acommander-in-chief would attribute his victory to the Christian God is a recurring motive since theConstantinian shift. Although theNew Testament nowhere mentions that divine battle aid could be gained from Christ,^[33] the Christian cross was known as a trophy to bestow victory sinceConstantine I and theBattle of the Milvian Bridge.

However, that a pagan like Clovis, could ask Christ for help also shows the adaptability of theGermanic polytheism. In the Germanic tradition,if Odin failed, one absolutely could try it with Christ for once.^[34] The Christian sense of religious exclusiveness, as obvious from theFirst Commandment, was unknown to the pagans. As a result, pagans could be pragmatic and almost utilitarian in their religious decisions. A good example for this are severalThor's Hammer with engraved crosses, worn as anamulet, that archaeologists have found inScandinavia.^[35] Another exemplary event happened duringAnsgar's second stay inBirka: A pagan priest demanded from the locals that they not participate in the cult of the foreign Christian God. If they did not have enough gods yet, they should elevate one of their deceased kings,Erik, to be a god.^[36]

The baptism of Clovis I also highlights the sacred role of the Germanic king. A Germanic king held the highest religious office for his people.^[37] He was seen as ofdivine descent, was the leader of thereligious cult and was responsible for the fertility of the land and military victory. Accordingly, the conversion of their leader had a strong impact on his people. If he considered it appropriate to adopt the Christian belief, this also was a good idea for them.

Thus early Germanic Christianity was presented as an alternative to nativeGermanic paganism and elements were syncretized, for example parallels betweenWoden andChrist. An illustration of these tendencies is theAnglo-Saxon poemDream of the Rood, where Jesus is cast in the heroic model of a Germanic warrior, who faces his death unflinchingly and even eagerly. TheCross, speaking as if it were a member of Christ's band of retainers, accepts its fate as it watches its Creator die, and then explains that Christ's death was not a defeat but a victory. This is in direct correspondence to the Germanic pagan ideals of fealty to one's lord.

The Georgian Orthodox Church became independent in 466 when the Patriarchate of Antioch elevated the Bishop ofMtskheta to the rank of "Catholicos of Kartli".

• Esler, Philip F.The Early Christian World. Routledge (2004).ISBN 0-415-33312-1.
• White, L. Michael.From Jesus to Christianity. HarperCollins (2004).ISBN 0-06-052655-6.
• Freedman, David Noel (Ed).Eerdmans Dictionary of the Bible. Wm. B. Eerdmans Publishing (2000).ISBN 0-8028-2400-5.
• Pelikan, Jaroslav Jan.The Christian Tradition: The Emergence of the Catholic Tradition (100-600). University of Chicago Press (1975).ISBN 0-226-65371-4.
• Trombley, Frank R., 1995.Hellenic Religion and Christianization c. 370-529 (in seriesReligions in the Graeco-Roman World) (Brill)ISBN 90-04-09691-4
• Fletcher, Richard,The Conversion of Europe. From Paganism to Christianity 371-1386 AD. London 1997.
• Schatz, Klaus (1996).Papal Primacy. Liturgical Press.ISBN 0-8146-5522-X.
• Schimmelpfennig, Bernhard (1992).The Papacy. Columbia University Press.ISBN 978-0-231-07515-2.

• Internet Ancient History Sourcebook: Christian OriginsArchived 2014-08-27 at theWayback Machine
• Guide to Early Church Documents
• Chart of Church Fathers at ReligionFacts.comArchived 2009-05-16 at theWayback Machine
• Church Fathers' works in English edited byPhilip Schaff, at theChristian Classics Ethereal Library
• Church Fathers at Newadvent.org
• Faulkner University Patristics Project A growing collection of English translations of patristic texts and high-resolution scans from the comprehensivePatrologia compiled by J. P. Migne.
• Primer on the Church Fathers at Corunum