Ignatius of Antioch in the context of "Catholic (term)"

Christianity in the ante-Nicene period was the period in Christian history following the Apostolic Age (1st century AD) up to the First Council of Nicaea (325 AD). Although the use of the term Christian (Koine Greek: Χριστιανός) is attested in the Acts of the Apostles (80–90 AD), the earliest recorded use of the term Christianity (Koine Greek: Χριστιανισμός) is attested by the ante-Nicene Father and theologian Ignatius of Antioch (c. 107 AD).

While the Jewish–Christian community was centered in Jerusalem in the 1st century AD, Gentile Christianity spread widely in the 2nd century AD. One stream of Gentile Christianity (so-called "proto-Orthodox Christianity") that emerged in this period in the persons and theological positions of the Apostolic Fathers would eventually become the international Great Church. Proto-Orthodox Christianity placed importance on the sacrifice of Jesus on the cross as saving humanity, and described Jesus as the incarnated Son of God come to Earth. The 2nd and 3rd centuries AD saw a sharp separation between Jewish Christianity and Gentile Christianity, with the latter being derived from the teachings of the Apostle Paul. There was an explicit rejection of Second Temple Judaism and Jewish culture by the end of the 2nd century, with a growing body of anti-Jewish Christian literature. Many doctrinal variations in this era defy neat categorizations, as various forms of Christianity interacted in a complex fashion.

The term Roman Catholic is sometimes used to differentiate the Catholic Church and its members in full communion with the pope in Rome from other Christians who identify as "Catholic". It is also sometimes used to differentiate adherents to the Latin Church and its use of the Roman Rite from Catholics of the Eastern Catholic Churches. It is not the official name preferred by the Holy See or bishops in full communion with the pope as a designation for their faith or institution.

The term "catholic" is one of the Four Marks of the Church set out in the Nicene Creed, a statement of belief widely accepted across Christian denominations. Catholics, Eastern Orthodox, and Oriental Orthodox consider the term "Catholic" to refer to a single institutional one true church, while Protestant ecclesiology considers it to refer to a church invisible referred to as the Christian Church. The use of "Roman" or "Roman Catholic" to differentiate the Catholic Church dates from the Middle Ages.

Various early Christian writers wrote gospels and other books, some of which were canonized as the New Testament canon developed. The Apostolic Fathers were prominent writers who are traditionally understood to have met and learned from Jesus's personal disciples. The Church Fathers are later writers with no direct connection to the disciples (other than the claim to apostolic succession). Early Christian apologists tried to defend Christianity against its critics, especially the Ancient Greek and Roman philosophers. Dates given, if not otherwise specified, are of their writings or bishopric, not of their lives.

• Paul of Tarsus, "Apostle to the Gentiles", earliest New Testament author 45~65
• Four Evangelists, traditionally identified as the authors of the canonical gospels 60~125
• Ignatius, bishop of Antioch, apostolic father 68~107
• Marcion of Sinope, evangelist and theologian, founder of Marcionism, published the first known canon of the New Testament, 85~160
• Clement of Rome, bishop of Rome, apostolic father 88~101
• Papias, bishop of Hierapolis, apostolic father 110~130
• Polycarp of Smyrna, bishop of Smyrna, apostolic father 110~160
• Aristides of Athens, apologist ~120
• Justin Martyr, church father ~165
• Melito of Sardis, bishop of Sardis, ~180
• Irenaeus, bishop of Lyon, disciple of Polycarp, apologist 180~202
• Origen of Alexandria, 185~254, Neoplatonist, controversial during his lifetime, posthumously condemned at the Second Council of Constantinople in 553
• Tatian, pupil of Justin Martyr, ascetic theologian ~185
• Athenagoras of Athens, philosopher, apologist ~190
• Polycrates, bishop of Ephesus, excommunicated by Victor I of Rome over the Easter controversy ~196
• Montanus, self-proclaimed prophet and founder of Montanism, last quarter of 2nd century CE
• Tertullian, church father, apologist, first Christian writer in Latin, later a Montanist 197~230
• Hippolytus, church father, sometimes termed the first Antipope, reconciled with the church and died a martyr 217~236
• Cyprian, bishop of Carthage, martyr 218~258
• Clement of Alexandria, church father, Bishop of Alexandria ~220
• Novatian, a rigorist and Antipope in 251
• Dionysius, patriarch of Alexandria, pope of the Coptic Orthodox Church 248~264
• Paul of Samosata, bishop of Antioch, adoptionist, condemned at 269 Council of Antioch
• Athanasius of Alexandria, c. 297~373, patriarch of Alexandria, defender of the Trinitarian doctrine
• Donatus Magnus, bishop of Carthage, (+355), leader of the Donatists from 313
• Lactantius, apologist ~317
• Arnobius, apologist ~330
• Eusebius, wrote History of the Church ~325
• Augustine of Hippo, 354-430, Latin church father, wrote Confessions and City of God

Church visible is a term of Christian theology and ecclesiology referring to the visible community of Christian believers on Earth, as opposed to the Church invisible or Church triumphant, constituted by the fellowship of saints and the company of the elect.

In ecclesiology, the Church visible has many names, such as Kingdom of God, Disciples of Christ and People of God. St. Ignatius of Antioch was one of the first Christian authors to write about the subject, insisting that the Church visible was centered on the Bishop and the Eucharist or Last Supper.

The term "Great Church" (Latin: ecclesia magna) is used in the historiography of early Christianity to mean the period of about 180 to 313, between that of primitive Christianity and that of the legalization of the Christian religion in the Roman Empire, corresponding closely to what is called the Ante-Nicene Period. "It has rightly been called the period of the Great Church, in view of its numerical growth, its constitutional development and its intense theological activity."

The Great Church, also called the catholic (i.e., universal) Church, has been defined also as meaning "the Church as defended by such as Ignatius of Antioch, Irenaeus of Lyons, Cyprian of Carthage, and Origen of Alexandria and characterized as possessing a single teaching and communion over and against the division of the sects, e.g., gnosticism, and the heresies".

The Epistle of Ignatius to the Smyrnaeans (often simply called Smyrnaeans) is an epistle from circa 110 AD attributed to Ignatius of Antioch, a second-century bishop of Antioch, addressed to the early Christians in Smyrna.

The term proto-orthodox Christianity or proto-orthodoxy describes the early Christian movement that was the precursor of Christian orthodoxy. Older literature often referred to the group as "early Catholic" in the sense that their views were the closest to those of the more organized "Catholic" Church that was the State church of the Roman Empire during the 4th and 5th centuries. The term "proto-orthodox" was coined by Bentley Layton, a scholar of Gnosticism and a Coptologist at Yale, but is often attributed to New Testament scholar Bart D. Ehrman, who has popularized the term by using it in books for a non-academic audience. Ehrman argues that when this group became prominent by the end of the third century, it "stifled its opposition, it claimed that its views had always been the majority position and that its rivals were, and always had been, 'heretics', who willfully 'chose' to reject the 'true belief'."

Although early Christianity had many diverse sects and doctrines, critics of the stance of downplaying the proto-orthodox's prominence (such as Larry W. Hurtado), generally argue that the writings of the Catholic anti-heresiologists condemning others as heretics were still essentially accurate: that of all the Christian groups, the "proto-orthodox" has the most common ground with the immediate followers of Jesus in the Apostolic Age and Christianity in the 1st century, and were indeed the most common variety of Christianity even then.