Heresies & councils

Must Gentile Christians be circumcised and keep the Mosaic law?

Some Jewish believers argued that Gentile Christians should be circumcised and observe the law of Moses. Acts 15 presents the apostles and elders addressing the dispute in Jerusalem; Paul’s letters show that related questions continued.

Some Jewish followers of Jesus believed circumcision and observance of Moses were necessary signs of covenant membership. Paul and others argued that Gentiles were incorporated through faith in Christ and the Spirit without first becoming Jews. The debate also involved food, table fellowship, and communal identity.

The decision opened a multi-ethnic church but did not end disagreement; Paul’s letters preserve continuing conflict. The episode helps learners distinguish the Torah’s place in Jewish life from the question of what was required of Gentile converts.

Christ only appeared to have a physical body

From the Greek dokein (“to seem”). Docetists taught that Christ’s body was an illusion. That claim undercut both the incarnation and the atonement.

Docetic tendencies treated Jesus’ bodily life and suffering as appearance, often because divine or spiritual reality was thought incompatible with matter. Opponents appealed to the incarnation, to touch, birth, suffering, and death, and to the bodily resurrection.

The dispute made Christ’s full humanity essential to salvation: what is not truly assumed, suffered, and raised cannot heal embodied human life. “Docetism” describes a family of tendencies, not one centrally organised church.

Jesus was a human Messiah, and all believers must keep the law of Moses

The Ebionites were Jewish followers of Jesus, known almost entirely from church writers from Irenaeus (c. 180) onward. Their name comes from the Hebrew ebyonim, “the poor”. They kept the law, including circumcision, rejected Paul as an apostate from it, and used a Gospel connected with Matthew. Most regarded Jesus as a man born to Joseph and Mary and chosen by God; Origen and Eusebius mention a second group who accepted the virgin birth but denied that Christ existed before it.

The Ebionites stressed the law given to Israel and saw Jesus as the promised prophet and Messiah, and they read Paul as having abandoned the law. Irenaeus and later writers replied that a merely human Jesus could not unite humanity to God, and they defended Paul’s letters as apostolic Scripture.

The dispute was about who Jesus is, and it should not be confused with Jewish identity as such. Jewish believers who keep parts of the law while confessing Christ’s divinity, in the early centuries or among Messianic Jews today, are not Ebionites. The sources are few and hostile, and historians disagree about how the various groups given this name related to one another.

The Creator God of Israel is a lesser, merely just god, distinct from the good Father revealed by Jesus; rejected the Jewish Scriptures

Marcion taught that the God of the Old Testament was a lesser, merely just god and that Jesus revealed a previously unknown good Father. He accepted only an edited Gospel related to Luke and a collection of Paul’s letters. His challenge contributed to discussion of which books were authoritative.

Marcion sharply separated the just creator proclaimed in Israel’s Scriptures from the previously unknown good God revealed by Jesus. He accepted an edited Gospel related to Luke and a collection of Pauline letters, while his critics defended one God, one creation, and continuity between Israel and the gospel.

The controversy pushed Christians to state more clearly how the Old and New Testaments belong together. It contributed to discussion of the canon, but the New Testament was not created by a single reaction to Marcion. Modern rejection of the Old Testament can reproduce a related error and foster anti-Judaism.

Secret knowledge saves; matter is evil and spirit is good

A broad label for varied second-century movements. Many such groups taught salvation through secret spiritual knowledge and held that the material world was made by an inferior deity, the Demiurge.

Groups now called Gnostic differed considerably. Many used myths of emanation and a lower creator to explain why divine spirits were trapped in the material world, with saving knowledge awakening them to their true origin. Writers such as Irenaeus defended the goodness of creation, public apostolic teaching, the incarnation, and bodily resurrection.

The category is a useful way into several second-century alternatives, but learners should not imagine one uniform Gnostic religion. Texts recovered in the last century, notably at Nag Hammadi, allow these movements to be studied in their own voices as well as through hostile reports.

New Prophecy claiming fresh revelations of the Spirit, stricter discipline, and an imminent New Jerusalem

The New Prophecy associated with Montanus, Prisca, and Maximilla arose in Phrygia c. 156–172. It emphasised ecstatic prophecy, strict discipline, fasting, and expectation of the New Jerusalem. Tertullian joined the movement c. 207. Most surviving descriptions come from opponents, so its precise teachings should be treated with caution.

Montanus, Prisca, and Maximilla led a prophetic movement emphasising the Spirit’s immediate speech, moral rigour, fasting, and expectation of the New Jerusalem. Critics questioned how its prophecy was tested, its discipline, and its authority. The surviving evidence does not support every later claim that the movement simply replaced Scripture.

The dispute asks how churches discern prophecy after the apostolic age and how charisma relates to ordered ministry. Because much of the evidence comes from opponents, it deserves more care than a simple conflict between revelation and Scripture.

Jesus was a man whom God empowered with his Spirit and adopted as his Son

Theodotus, a leather-worker from Byzantium known as “the Cobbler”, taught in Rome that Jesus was a man on whom the Spirit, or the Christ, came down at his baptism. Bishop Victor of Rome excommunicated him. Later Paul of Samosata, bishop of Antioch, taught that the divine Word dwelt in the man Jesus as in a temple, and a synod at Antioch deposed him in 268. “Dynamic Monarchianism” is a modern label for views that kept God’s oneness (monarchia) by treating Christ as a man filled with divine power (dynamis).

Adoptionists wanted to guard the oneness of God and the real humanity of Jesus, and they read the accounts of his baptism and exaltation as the moment he became God’s Son. Their opponents argued from passages such as John 1:1–14 and Philippians 2:5–11 that the Son was divine before the incarnation and is God’s Son by nature.

Adoptionism and modalism were opposite answers to one question, how to confess one God and a divine Christ, and the church rejected both. Later writers report that the synod against Paul also rejected the word homoousios, which made the term suspect to some bishops after Nicaea. A different Adoptionism arose in eighth-century Spain and was condemned at the Council of Frankfurt in 794.

The baptismal creed of the Western church, traditionally divided into twelve articles

The creed grew from the Old Roman Symbol, a baptismal confession whose earlier forms were in use in Rome by about 200. Marcellus of Ancyra (c. 340) and Rufinus (c. 404) give its text in full, and Rufinus also records the legend that each of the twelve apostles contributed a clause. Phrases such as “he descended into hell” and “the communion of saints” entered local versions over the following centuries, and the text used today appears in the early eighth century.

The creed follows the pattern of baptism in the name of the Father, the Son, and the Holy Spirit (Matthew 28:19). It arose before the fourth-century debates and says little about how Christ is God. Its emphasis falls on events: the Son was born of the Virgin Mary, suffered under Pontius Pilate, was crucified, died, was buried, and rose again.

Catholic, Anglican, Lutheran, Reformed, Methodist, and many other Protestant churches use it in baptism, catechesis, and daily prayer. The Eastern Orthodox churches never adopted this Western text and do not use it in worship, though its teaching is also found in the Nicene Creed, which they confess.

Father, Son, and Spirit are three modes of one person

Taught that God is a single person who revealed himself in three successive modes. It denied the real distinction of persons in the Trinity. An earlier form, often called Patripassianism (“the Father suffered”), was taught by Noetus in Smyrna (c. 200) and by Praxeas in Rome. Tertullian answered Praxeas in Against Praxeas (c. 213), complaining that he had “crucified the Father”.

Modal accounts protected God’s unity by treating Father, Son, and Spirit as ways the one God appears or acts, not as eternally distinct persons. Their critics argued that the baptism of Jesus, prayer to the Father, and the sending of the Spirit require real relation within the one divine life.

The controversy helped Christians articulate both one divine being and three distinct persons without teaching three gods. Modern analogies such as water, ice, and steam often drift towards modalism and can obscure those eternal relations.

Can Christians who denied the faith under persecution be restored to communion?

During the persecution under Emperor Decius (250–51), many Christians offered sacrifice or bought certificates saying they had done so. When Cornelius was elected bishop of Rome in 251 and allowed these “lapsed” to return after penance, the presbyter Novatian, an able theologian, was consecrated as a rival bishop. He held that the church had no power to restore those who had denied Christ. His followers formed a separate church that lasted for several centuries.

Novatian and his supporters believed that a church which readmitted apostates had compromised its holiness, and they left such sinners to God’s judgment. Cornelius and Cyprian of Carthage held that the church could restore them after a period of penance; Cyprian also resisted confessors who wanted the lapsed restored at once. Cyprian set out his case in On the Lapsed and On the Unity of the Catholic Church (251).

The Novatianists were orthodox about the Trinity, so the division concerned discipline and the nature of the church. The Council of Nicaea (canon 8) later set terms for receiving their clergy. The same questions about forgiveness and the purity of the church returned in the Donatist schism.

Does a sacrament depend on the holiness of the minister who performs it?

In 311 Caecilian was consecrated bishop of Carthage. His opponents claimed that one of the bishops who consecrated him had been a traditor, someone who handed over the Scriptures to be burned during Diocletian’s persecution, and they elected a rival bishop, soon succeeded by Donatus. The Donatists saw themselves as the true church of the martyrs and rebaptised Christians who joined them. The division dominated North African Christianity for a century.

Donatists held that a bishop who had betrayed the faith lost the Spirit and could not give valid sacraments, so a church in communion with such bishops was polluted. Augustine replied that Christ is the true minister of baptism, so a sacrament given in the church’s form is valid even when the minister is unworthy. He also argued that the church on earth mixes wheat and weeds until the final judgment (Matthew 13:24–30).

Catholic, Orthodox, and Protestant churches agree that a sacrament’s validity does not rest on the minister’s personal holiness. The Augsburg Confession (Article 8) names and condemns the Donatists, and the Anglican Thirty-Nine Articles (Article 26) make the same point. Augustine’s later support for imperial force against the Donatists, argued from Luke 14:23, “compel them to come in” (KJV), was cited for centuries to defend coercion in religion.

The Son is the highest creature, not eternal God

Arius taught that the Son was the first creation of the Father: “there was when he was not”. This denied the full deity of Christ and led to the Council of Nicaea.

Arius taught that the Son came from the Father’s will and therefore had a beginning, even though the Son was pre-eminent over all other creatures. His opponents argued that Christian worship and salvation require the Son to share fully and eternally in the Father’s divine being.

The debate concerned biblical interpretation, worship, and salvation as well as a single disputed word. Fourth-century positions changed and cannot all be reduced to Arius. Communities now called Arian should not automatically be equated with every modern non-Trinitarian group.

Response to the Arian controversy

The first council later recognised as ecumenical was called by Emperor Constantine. Tradition numbers its bishops as 318. Its creed rejected Arius’s teaching and used the term homoousios to confess the Son’s full divinity.

The bishops rejected the claim that the Son was made from nothing and confessed him as begotten from the Father’s substance and homoousios with the Father. The creed’s non-biblical term was chosen to guard a biblical conviction, though participants did not yet agree on every later technical distinction.

Nicaea became a foundation for Trinitarian orthodoxy, but controversy continued for decades. Catholic, Orthodox, and most Protestant churches receive its core confession. The council’s imperial setting also raises lasting questions about political power and doctrinal decision-making.

Christ had no human mind; the Logos replaced it

Apollinaris taught that the divine Logos took the place of the human rational soul in Christ. Gregory of Nazianzus answered: “What is not assumed is not healed.”

Apollinaris sought to secure Christ’s unity by assigning the divine Word the role of the human rational mind. Opponents agreed that Christ is one but insisted that he has a complete human nature (body, mind, will, and soul) united to divinity.

The response established a lasting principle, summed up by Gregory of Nazianzus: “What is not assumed is not healed.” Salvation reaches every dimension of humanity because Christ assumed a complete humanity. The dispute prepared the way for later, more precise arguments about person and nature.

Response to continuing Trinitarian and Christological disputes

The second council later recognised as ecumenical reaffirmed Nicaea, rejected Apollinarian teaching, and became central to the church’s received Trinitarian confession.

The council supported Nicene teaching, opposed several rival Trinitarian and Christological positions, and confessed the Holy Spirit as Lord and giver of life, who is worshipped and glorified with the Father and the Son. The creed used in churches today reflects this Nicene-Constantinopolitan tradition.

Its reception helped stabilise pro-Nicene Trinitarian language. The Filioque (“and the Son”) was not part of the creed as issued. Western churches later added it (at Toledo in 589, and in Rome in 1014), and the addition became a major dispute between Eastern and Western churches.

The creed of Nicaea (325) as expanded and received after the Council of Constantinople (381)

The Council of Nicaea issued a short creed in 325 that ended with belief in the Holy Spirit and was followed by anathemas against Arian teaching. The longer creed now called the Nicene Creed is linked with the Council of Constantinople in 381. It keeps Nicaea’s confession that the Son is “of one substance with the Father” and adds clauses on the Holy Spirit, the church, baptism, and the resurrection. Its text is first recorded in the acts of Chalcedon (451).

Scholars call this text the Niceno-Constantinopolitan Creed. It was probably adapted from an existing baptismal creed, and historians debate its exact origin. Its later history includes the Filioque: Western churches added that the Spirit proceeds from the Father “and the Son”, a phrase the Eastern Orthodox reject as an addition made without an ecumenical council and, for many, as theologically mistaken.

It is the most widely shared Christian creed. Catholic, Eastern Orthodox, Oriental Orthodox, Anglican, Lutheran, Reformed, and many other churches confess it, and many recite it at the Eucharist. Because it is shared so widely, it is the usual standard for judging whether a teaching about God belongs to historic Christian faith.

Human nature is able to obey God without inward, enabling grace

Pelagius stressed moral responsibility and taught that people are able to choose righteousness. He did speak of grace, but he understood it as the gifts of nature, the law, Christ’s example, and forgiveness, not as an inward power that enables the will. He also denied that Adam’s sin is passed on to his descendants.

Pelagius emphasised moral responsibility and opposed excuses for sin. Augustine argued that humanity’s will is so wounded by sin that prevenient and transforming grace is necessary for every saving good. The historical Pelagius may not have held every proposition later grouped under his name.

The controversy set the terms of Western teaching on original sin, baptism, freedom, grace, and predestination. Catholic, Orthodox, Lutheran, Reformed, and Wesleyan traditions all reject self-salvation but explain inherited sin and enabling grace differently.

Does the first movement towards faith come from God’s grace or from the human will?

In the 420s monks in North Africa and southern Gaul questioned Augustine’s late teaching on grace and predestination. John Cassian of Marseille (Conferences 13) argued that the first desire for good sometimes comes from God and sometimes from the human will, which grace then helps. Prosper of Aquitaine defended Augustine. Later Faustus of Riez (On Grace, c. 470s) taught that the will can take the first step towards faith, aided by grace. The label “Semi-Pelagian” dates from the sixteenth century; historians often call these writers Massilians, after Marseille.

Cassian and Faustus rejected Pelagius and held that grace is necessary for salvation, but they feared that Augustine’s account of predestination made human effort pointless. Augustine and Prosper replied that faith itself, including its beginning, is God’s gift (1 Corinthians 4:7; Philippians 1:29). Orange sided with Augustine on the priority of grace, condemned the idea that anyone is predestined to evil, and left his fuller teaching on predestination unaddressed.

Orange’s canons were little known in the Middle Ages and drew new attention in the sixteenth century, when Catholics and Protestants both appealed to them. Western churches today reject Semi-Pelagianism, though they still disagree about how grace and the will relate. The Orthodox Church honours Cassian as a saint, and Orthodox teaching on synergy does not follow the Western framing of this debate.

How should Christians speak of Christ’s unity and Mary’s title Theotokos?

Cyril of Alexandria argued that Nestorius’s language divided Christ too sharply. Nestorius rejected that reading of his teaching, and modern scholars continue to debate how closely later “Nestorianism” represents his own position. The Church of the East does not accept the label as a description of its Christology.

Cyril feared that Nestorius’s resistance to Theotokos divided the one Christ into two acting subjects. Nestorius feared language that confused the divine and human natures or implied that divinity itself originated from Mary. Political, linguistic, and personal conflict sharpened their theological disagreement.

The dispute established that statements about Jesus’ human birth and suffering refer to the one divine Son incarnate. The Assyrian Church of the East rejects the label “Nestorian”, and modern dialogue has found substantial shared Christological faith beneath inherited terminology.

Response to Nestorius

The third council later recognised as ecumenical. It endorsed the teaching of Cyril of Alexandria and affirmed the title Theotokos to safeguard the unity of Christ’s person. The Church of the East did not receive the council.

The council supported Cyril’s teaching and condemned Nestorius, confessing that the one born from Mary is the Word incarnate. Its turbulent proceedings included rival assemblies and imperial intervention, so the result cannot be understood from the doctrinal formula alone.

Theotokos protects a claim about Christ before it makes a claim about Mary: the person she bore is truly God the Son in human flesh. Catholic, Eastern Orthodox, Oriental Orthodox, and most Protestant traditions accept this. The Church of the East, which did not receive the council, remembers the conflict differently.

Christ’s humanity is absorbed into one nature after the incarnation

Eutyches was understood to teach that Christ’s humanity was absorbed into a single incarnate nature. Chalcedon rejected this account. Oriental Orthodox miaphysite theology also rejects Eutychianism and should not be confused with it, even though older polemics often used the label “Monophysite” for both.

Eutyches defended Christ’s unity but was understood to leave his humanity no longer consubstantial with ours after the incarnation. Chalcedonian opponents confessed one and the same Son in complete divinity and complete humanity, without confusion or division.

The episode shows why Christ’s unity must not erase his humanity. Oriental Orthodox miaphysite churches also reject Eutyches; describing them as Eutychian or simply Monophysite misrepresents their teaching and ignores modern ecumenical clarification.

Response to Eutychianism

The fourth council later recognised as ecumenical by Chalcedonian churches; its definition was not received by the Oriental Orthodox. The four adverbs answered Eutyches and Nestorius together.

Chalcedon received Leo’s Tome and Cyril’s earlier teaching, confessing one person in two natures, complete in divinity and humanity. Its four safeguards (without confusion, without change, without division, without separation) set boundaries for speaking of Christ without claiming to explain the mystery.

Catholic, Eastern Orthodox, Anglican, and most Protestant churches receive Chalcedon. Oriental Orthodox churches rejected its wording and the process that produced it, although modern dialogues report substantial agreement about Christ and distinguish their miaphysite theology from Eutychianism.

A Latin summary of the Trinity and the incarnation, beginning Quicunque vult (“Whoever wishes to be saved”)

The creed bears the name of Athanasius of Alexandria, but he did not write it. It was composed in Latin, probably in southern Gaul in the late fifth or early sixth century. It uses Augustine’s Trinitarian language and answers Christological questions that arose after Athanasius died in 373. Caesarius of Arles (d. 542) is the earliest writer known to quote it, and its author is unknown.

The creed states the Trinity in balanced formulas: “we worship one God in Trinity, and Trinity in Unity”, with the Father, the Son, and the Holy Spirit each eternal and almighty, yet one God. It then confesses Christ as perfect God and perfect man. Its opening and closing clauses warn that whoever does not keep this faith will perish, and these “damnatory clauses” have long been debated.

Lutheran and Reformed confessions and the Anglican Thirty-Nine Articles (Article 8) receive it with the Apostles’ and Nicene creeds, and the Catholic Church long recited it in the Divine Office. The Eastern Orthodox do not use it in worship, partly because it says the Spirit proceeds from the Father and the Son. Many churches that accept its teaching now recite it rarely.

Clarified Chalcedon; condemned the Three Chapters

The fifth council later recognised as ecumenical. It condemned writings by Theodore of Mopsuestia, Theodoret of Cyrrhus, and Ibas of Edessa that were judged Nestorian.

The council condemned the Three Chapters (the person and writings of Theodore of Mopsuestia, certain writings of Theodoret, and a letter attributed to Ibas) to show that Chalcedon should be read in continuity with Cyril and gave no cover to Nestorian teaching.

Its attempt at reconciliation did not restore communion with non-Chalcedonian churches and provoked new resistance in the West. The council shows how later interpretation can become as contested as an original doctrinal definition.

Christ has one will, although he has two natures

Emperor Heraclius and Patriarch Sergius of Constantinople hoped to reconcile Chalcedonian and miaphysite Christians. From 633 they promoted the teaching that Christ has one activity, and when Sophronius of Jerusalem objected, they turned instead to one will. Heraclius’s Ecthesis (638) forbade talk of one or two activities and confessed one will in Christ. Pope Honorius I had already written of “one will” in a letter to Sergius.

Monothelites argued that one person can have only one will, and that a second, human will would set Christ against himself. Maximus the Confessor answered that will belongs to nature: because Christ is fully human, he has a human will, which freely obeys the divine will, as in Gethsemane: “yet not my will, but yours be done” (Luke 22:42, NIV).

Maximus and Pope Martin I opposed the imperial policy and suffered for it. Martin died in exile in 655, and Maximus died in 662 after his tongue and right hand were cut off. Constantinople III vindicated their teaching. The dispute established that Christ’s human obedience is real, which matters for how Christians understand his temptation and his saving obedience.

Response to Monothelitism

The sixth council later recognised as ecumenical. It condemned Monothelitism and posthumously condemned Pope Honorius I, the only pope formally condemned by an ecumenical council.

Monothelite proposals taught one will or mode of willing in Christ, partly as an attempted bridge after Chalcedon. The council confessed two natural wills and operations, divine and human, acting in harmony in the one person of Christ.

The decision protects Christ’s full human agency and obedience: salvation involves a human will healed and united with God. The condemnation of Pope Honorius later became important in debates over papal authority and the precise scope of infallibility.

May Christians make and venerate images of Christ and the saints?

Emperor Leo III began acting against icons around 726–30, and his son Constantine V had them condemned at the Council of Hieria (754). Empress Irene called the Second Council of Nicaea, which restored them in 787. Leo V renewed iconoclasm in 815. It ended in 843 under Empress Theodora, and the Orthodox Church celebrates that restoration each year on the first Sunday of Lent as the Triumph of Orthodoxy. Most surviving sources were written by the icons’ defenders, and historians debate how far Leo III himself went.

Iconoclasts cited the command against graven images (Exodus 20:4–5) and argued that Christ’s divinity cannot be depicted, so an image of him either divides his natures or confuses them. John of Damascus and later Theodore the Studite replied that in the incarnation the invisible God became visible, and that honour given to an image passes to the one it depicts.

Catholic and Orthodox churches receive Nicaea II and regard iconoclasm as a heresy. The classification is not shared by all: the Frankish Council of Frankfurt (794) rejected Nicaea II’s decrees as it understood them from a poor Latin translation, and many Reformed Protestants later opposed religious images in worship. Lutherans generally kept images in churches without adopting icon veneration.

Response to Iconoclasm

The seventh council later recognised as ecumenical, and the last received by both the Catholic and Eastern Orthodox churches. It distinguished latreia, the worship due to God alone, from timētikē proskynēsis, the honorific veneration given to icons.

Iconoclasts opposed sacred images as violations of the command against idolatry, while defenders argued that because the Word truly became visible flesh, Christ may be depicted. The council distinguished the worship owed to God alone from the relative veneration shown to an image and its prototype.

Catholic and Orthodox churches receive the council, while many Protestants do not treat it as ecumenically binding and differ among themselves about images. The controversy connects incarnation, worship, political power, memory, and the education of worshippers.

A symbolic milestone in the gradual rupture between Rome and Constantinople

The separation of Eastern and Western churches developed over centuries. Disputes included papal primacy, the Filioque, liturgical practice, language, and politics. In 1965 Catholic and Orthodox leaders lifted the anathemas of 1054, though the schism itself continues.

Eastern and Western estrangement involved competing claims about Roman primacy, the Filioque, jurisdiction, liturgy, language, and imperial politics. The excommunications of 1054 were aimed at particular individuals. They took on symbolic weight only later, as part of a longer estrangement that included the sack of Constantinople in 1204.

Catholic and Orthodox churches remain out of full communion despite extensive modern dialogue and mutual recognition in important areas. Treating the schism as one argument or one date hides centuries of shared life, local variation, and failed reconciliation.

Diverse medieval dualist movements rejected central Catholic teachings and institutions

Movements labelled Cathar flourished especially in parts of southern France and northern Italy. Sources attribute to them forms of dualism, rejection of Catholic sacraments, and a demanding spiritual elite, but much of the evidence comes from opponents, and historians debate how unified the movement was.

Cathar groups appear to have held diverse dualist teachings that opposed spiritual good to corrupt matter and rejected parts of Catholic sacramental and clerical life. Knowledge of them comes largely through inquisitorial and polemical sources, so historians debate how coherent or widespread a single Cathar church was.

The response combined preaching, institutional reform, crusading violence, and inquisition. Learners must separate the evaluation of a theology from moral approval of coercion: declaring ideas false does not justify massacre, dispossession, or forced conversion.

May lay Christians living in poverty preach without a bishop’s permission?

Around 1175 Valdes, a wealthy merchant of Lyon later called Peter Waldo, gave away his property, had parts of Scripture translated into the local language, and began to preach. Pope Alexander III approved his vow of poverty at the Third Lateran Council (1179) but forbade him to preach without the local clergy’s permission. When Valdes and his followers, the Poor of Lyon, kept preaching, the decree Ad abolendam, issued at Verona in 1184, condemned them. The movement survived persecution, especially in the Alpine valleys of Piedmont.

Valdes signed an orthodox profession of faith at Lyon in 1180, and the first dispute concerned the authority to preach. Over time many Waldensians rejected purgatory, prayers for the dead, and oath-taking. Catholic authorities saw unlicensed preaching and these teachings as a threat to the church’s order and doctrine, while Protestants later regarded the Waldensians as forerunners of the Reformation.

At Chanforan in 1532 the Waldensians adopted Reformed theology, and the Waldensian Evangelical Church still exists in Italy, united with Italian Methodists since 1975. They suffered massacres, notably in Piedmont in 1655, and gained civil rights in 1848. In 2015 Pope Francis visited their church in Turin and asked forgiveness for the Catholic Church’s treatment of them.

Catholic council on doctrine, the sacraments, and church discipline

Called by Pope Innocent III. Its opening creed says the bread and wine are “transubstantiated” into Christ’s body and blood, the first conciliar use of the term; the Council of Trent later defined the doctrine more fully. The council also required annual confession and Communion.

The council addressed doctrine, clerical reform, the sacraments, crusade, and relations with Jews and Muslims. Its creed used “transubstantiated” to affirm that the bread and wine become Christ’s body and blood, and it required the faithful to confess annually and receive Communion at Easter.

It had a lasting effect on medieval Catholic practice and language. Its discriminatory requirements for Jews and Muslims and its support for coercive policies require frank ethical attention. Protestant traditions later rejected or reinterpreted several of its sacramental conclusions.

Debates over authority, the Eucharist, reform, and vernacular Scripture

John Wycliffe criticised papal authority and transubstantiation and supported vernacular access to Scripture. Followers associated with Lollardy developed a wider reform movement. Later Protestants treated parts of his legacy more positively than medieval Catholic authorities did.

Wycliffe attacked clerical wealth and papal claims, grounded authority in grace, criticised transubstantiation, and supported vernacular Scripture. Lollard communities adopted overlapping but varied reforming positions; neither Wycliffe nor the movement maps exactly onto later Protestantism.

Their suppression shows how theological authority, literacy, property, and political stability were intertwined. Later Protestants remembered Wycliffe as a forerunner, while Catholic judgment emphasised teachings it considered errors about church and sacrament.

Two, and later three, rival popes divided the loyalty of the Western church

After the papacy returned from Avignon to Rome, the cardinals elected Urban VI in 1378 under pressure from Roman crowds. Within months most of them declared the election invalid and chose Clement VII, who settled in Avignon. Rulers took sides: France, Scotland, and the Spanish kingdoms backed Avignon, while England and most of the Empire and Italy backed Rome. The Council of Pisa (1409) deposed both popes and elected a third, Alexander V, but neither of the others gave way.

Each claimant had supporters among saints, scholars, and rulers, and the question was which election was valid, not a matter of doctrine. The deadlock strengthened conciliarism, the view that a general council holds authority in the church that even a pope must obey. Constance stated this in its decree Haec sancta (1415).

At Constance, John XXIII of the Pisan line was deposed, Gregory XII of the Roman line resigned, and Benedict XIII of the Avignon line was deposed, clearing the way for Martin V. The Catholic Church now lists the Roman line as the legitimate popes, which is why a later pope could take the name John XXIII in 1958. Catholics still debate what authority Haec sancta holds.

Calls for church reform and disputes over authority and Communion

Jan Hus criticised corruption and drew on some of Wycliffe’s ideas while developing his own reform programme. His execution intensified conflict in Bohemia, where Hussite communities continued and diversified.

Hus preached moral reform and challenged corrupt authority, drawing selectively from Wycliffe while remaining distinct from him. At Constance he disputed whether the condemned propositions represented his views and refused an unconditional recantation. Hussites later developed several theological and political programmes.

His execution despite a promise of safe conduct is remembered as a case of conscience against institutional injustice. Catholic–Hussite dialogue has since reassessed the conflict, and his followers shaped Bohemian religion long before Luther.

Catholic council that sought reunion with the Orthodox and other Eastern churches

Pope Eugenius IV opened the council at Ferrara in 1438 and moved it to Florence in 1439, and later to Rome. Emperor John VIII Palaiologos and Patriarch Joseph II came with a large Greek delegation, hoping for Western help against the Ottoman Turks. The decree of union, signed in July 1439, affirmed the Filioque, purgatory, the use of either leavened or unleavened bread, and papal primacy. The Catholic Church counts Florence as an ecumenical council; the Orthodox churches do not.

Latin and Greek theologians debated at length, and most Greek bishops signed, some under heavy pressure. Mark of Ephesus refused, holding that the Latin addition to the creed and its theology could not be accepted. Supporters of union, such as Bessarion of Nicaea, believed that the Greek and Latin fathers taught the same faith in different words.

Clergy and people in the East largely rejected the union. It was proclaimed in Hagia Sophia in December 1452, months before Constantinople fell to the Ottomans in 1453. Florence also made short-lived unions with Armenian, Coptic, and other churches. Its decrees remain part of Catholic teaching, and the Orthodox honour Mark of Ephesus as a saint.

Began the dispute that grew into the Protestant Reformation

On 31 October 1517 Martin Luther challenged the preaching of indulgences, and the dispute soon spread across Europe. The Theses targeted indulgences; his teaching on justification by faith alone developed in the following years.

The theses questioned the preaching and theological assumptions surrounding indulgences, especially claims that payment could secure release from punishment. Luther first framed an academic dispute; his positions on authority and justification developed through later conflict.

Print, politics, pastoral anxiety, and demands for reform turned the episode into a wider rupture. The event is a useful doorway into the Reformation, but neither the five solas nor Luther’s mature doctrine is contained in the 95 Theses.

Catholic council responding to Protestantism

The council met in three periods between 1545 and 1563. It affirmed apostolic tradition alongside Scripture, rejected justification by faith alone, and reaffirmed all seven sacraments.

Trent answered Protestant challenges while pursuing Catholic reform. It treated Scripture and apostolic tradition, defined justification as entirely initiated by grace yet involving real renewal and cooperation, reaffirmed seven sacraments, and legislated for clergy education and pastoral discipline.

Its decrees governed Catholic life worldwide for centuries. Protestants reject several of its conclusions, but modern ecumenical dialogue has corrected caricatures on both sides. Catholic teaching does not say salvation is earned without grace, and classic Protestant teaching does not make a transformed life optional.

Denied the Trinity and the divinity of Christ; a forerunner of Unitarianism

Laelius and Faustus Socinus developed a rationalist theology that rejected the Trinity and substitutionary atonement. The movement was centred in Poland among the Polish Brethren, whose Racovian Catechism (1605) influenced later Unitarian thought.

The Polish Brethren and thinkers associated with Fausto Sozzini rejected Nicene Trinitarianism, Christ’s personal pre-existence, and satisfaction accounts of the atonement. They emphasised rational interpretation, moral discipleship, and often religious toleration, though the movement was internally diverse.

Socinian writings influenced later Unitarian and rational-dissenting currents, but the history is not a single straight line to every modern Unitarian community. The controversy shows how appeals to Scripture and reason can produce sharply different conclusions about Jesus and salvation.

Debates over election, atonement, grace, and perseverance, answered by a Reformed synod

Followers of Jacob Arminius presented the Remonstrance of 1610. The Synod of Dort answered it from a Reformed perspective. Arminian theology later became important in Methodist, Wesleyan, and other Protestant traditions, which do not regard it as heresy.

The Remonstrants taught conditional election, universal provision in Christ’s atonement, the necessity of grace, and resistible grace, and at first left perseverance an open question. Dort defended unconditional election, particular redemption, effectual calling, radical human inability, and the preservation of the saints, while rejecting the Remonstrant articles.

Both sides claimed biblical and Reformation roots, and later Wesleyan Arminianism was not identical to the original Remonstrance. The five points summarise one controversy, not either tradition’s whole theology. Most participants affirmed the necessity of grace and rejected salvation by unaided will.

How does God’s grace act on the human will, and how strict should Christian life be?

Cornelius Jansen, bishop of Ypres, died in 1638, and his study of Augustine, the Augustinus, appeared in 1640. It became the rallying point for a movement centred on the convent of Port-Royal near Paris, with Antoine Arnauld and Blaise Pascal among its defenders. Jansenists accepted Rome’s condemnation of the five propositions but denied that Jansen had taught them in the sense condemned. Louis XIV had Port-Royal destroyed in 1710–11, and resistance to Unigenitus divided the French church for decades.

Jansenists read Augustine as teaching that fallen humans cannot resist efficacious grace, and they called for deep contrition and moral seriousness. Their opponents, especially Jesuits, held that sufficient grace is given to all and that Jansenism came close to Calvinism. Pascal’s Provincial Letters (1656–57) attacked Jesuit moral theology as too lax.

The dispute ran within the Catholic Church: Jansenists saw themselves as loyal Catholics and rejected Calvinism. It influenced French spirituality, including a reluctance to receive Communion often. A related dispute led the Church of Utrecht to break with Rome in 1723, and it later became part of the Old Catholic movement.

Reason alone can know God, who made the world but does not reveal himself through miracles or Scripture

Deism was a loose current of thought in England from the late seventeenth century, later influential in France and America. John Toland’s Christianity Not Mysterious (1696) argued that nothing in true religion is contrary to or above reason. Matthew Tindal’s Christianity as Old as the Creation (1730) presented the gospel as a republication of the religion of nature. Voltaire and Thomas Paine (The Age of Reason, 1794) later spread similar ideas.

Deists held that a rational religion of one God, moral duty, and future reward was sufficient, and many doubted miracles, prophecy, and doctrines such as the Trinity. Christian critics, including Butler, argued that natural religion faces the same difficulties as revealed religion, and that the evidence for Scripture’s history and miracles deserved serious weight.

Deism had no church or creed, and no council condemned it; Catholic and Protestant writers answered it in books and sermons. The debate raised questions about revelation, miracles, and the reliability of the Gospels that remain in modern apologetics. Several of America’s founders, among them Thomas Jefferson, held views close to it.

New movements that call themselves Christian but do not confess the Trinity as the Nicene Creed does

Three of the largest such movements began in North America. The Church of Jesus Christ of Latter-day Saints was organised by Joseph Smith in New York in 1830, the year the Book of Mormon was published. Jehovah’s Witnesses grew from the Bible Student movement led by Charles Taze Russell from the 1870s and took their present name in 1931. Oneness Pentecostalism arose from a 1913 camp meeting near Los Angeles, after which some Pentecostals began to baptise “in the name of Jesus” (Acts 2:38); when the Assemblies of God adopted a Trinitarian statement in 1916, Oneness ministers left. All three call themselves Christian.

Latter-day Saints teach that the Father, the Son, and the Holy Ghost are three distinct beings, one in purpose, and that the Father and the Son each have a glorified body of flesh and bone; Jesus Christ is the divine Son of God and the Saviour of the world. Jehovah’s Witnesses teach that Jehovah alone is almighty God, that Jesus is God’s Son and his first creation, through whom all other things were made, and that the holy spirit is God’s active force, not a person. Oneness Pentecostals teach that there is one God, fully revealed in Jesus Christ, and that Father, Son, and Holy Spirit are manifestations of that one God, not distinct persons.

The three movements differ sharply from each other. Oneness Pentecostals confess Jesus as fully God, Jehovah’s Witnesses deny that he is almighty God, and Latter-day Saints describe him as a divine being distinct from the Father. Trinitarian critics liken Oneness teaching to ancient modalism and Witness teaching to Arianism, though neither comparison is exact. In 2001 the Catholic Church ruled that Latter-day Saint baptism is not valid Christian baptism.

Catholic council that defined papal infallibility

Vatican I defined that the pope, when speaking ex cathedra on faith and morals, is preserved from error by divine assistance.

Vatican I taught that the pope is preserved from error when, as universal pastor, he definitively teaches a doctrine of faith or morals to be held by the whole church. It did not claim that every papal opinion, sermon, policy, or private statement is infallible.

Catholics receive the definition in relation to the church’s wider teaching authority; Orthodox, Old Catholic, Anglican, and Protestant traditions reject or substantially qualify it. The council was cut short by war in 1870, leaving its teaching on the church to be complemented by Vatican II’s teaching on bishops and the whole people of God.

Debates over biblical criticism, miracles, doctrine, and Christianity’s relation to modern thought

Modernist theologians reinterpreted traditional claims in conversation with historical criticism and modern science. Critics such as J. Gresham Machen argued that core Christian doctrines were being abandoned. Both movements were diverse, so individual thinkers should be assessed by their actual claims.

Modernists sought to reinterpret Christianity through historical criticism, science, and modern accounts of experience. Fundamentalists defended doctrines they considered essential, including biblical authority, Christ’s divinity, atonement, resurrection, and miracles. Many Christians occupied mediating positions, so neither label names one uniform theology.

The conflict reshaped seminaries, denominations, missions, and public religion, especially in North America. It still influences arguments about Scripture and science, but using the old labels carelessly can conceal major differences within contemporary evangelical, mainline, Catholic, and Orthodox thought.

Catholic council for renewal in liturgy, church life, ecumenism, and engagement with the modern world

Vatican II encouraged fuller participation in the liturgy and permitted wider use of vernacular languages while retaining Latin. It renewed Catholic approaches to Scripture, ecumenical dialogue, other religions, the role of the laity, and religious liberty. Not every later change commonly associated with “Vatican II” was directly commanded by the council.

Vatican II presented the church as the people of God and as sacrament, encouraged active liturgical participation, renewed engagement with Scripture, affirmed religious liberty, addressed other Christians and religions, and described the church’s mission in the modern world. Its sixteen documents differ in genre and authority.

Catholics continue to debate interpretation and implementation through the council’s actual texts and later reforms. Other Christians often view its ecumenical openness positively. The council did not abolish Latin, invent every postconciliar change, or reverse all prior Catholic teaching.

How does divine foreknowledge relate to genuinely free future choices?

Open theists argue that some future free choices are not yet definite objects of knowledge, while critics say this conflicts with classical accounts of divine omniscience and providence. Most Arminian traditions affirm exhaustive divine foreknowledge and therefore distinguish their position from open theism.

Open theists affirm God’s perfect knowledge of everything knowable but argue that some future free decisions are possibilities, not settled facts. Classical theists respond that God eternally knows future contingents without causing them and that exhaustive foreknowledge supports prophecy, providence, and trust.

The debate concerns the nature of time, freedom, prayer, risk, and divine responsiveness. Open theism is not simply classical Arminianism, since most Arminians affirm exhaustive foreknowledge. Christian traditions also offer models beyond the main modern evangelical framing.