Early centers of Christianity in the context of "Epistle to the Galatians"

The Greek Orthodox Patriarchate of Jerusalem, also known as the Greek Orthodox Church of Jerusalem, is an autocephalous church within the wider communion of Eastern Orthodox Christianity. Established in the mid-fifth century as one of the oldest patriarchates in Christendom, it is headquartered in the Church of the Holy Sepulchre in Jerusalem and led by the patriarch of Jerusalem, currently Theophilos III. The patriarchate's ecclesiastical jurisdiction includes roughly 200,000 to 500,000 Orthodox Christians across the Holy Land in Palestine, Jordan and Israel.

The church traces its foundation in Jerusalem to the day of Pentecost, when the Holy Spirit, according to Christian beliefs, descended on the disciples of Jesus Christ and ushered the spread of the Gospel. The church celebrates its liturgy in the ancient Byzantine Rite – whose sacred language, Koine Greek, is the original language of the New Testament – and follows its own liturgical year under the Julian calendar.

Christianity is the second largest religion in Egypt. The vast majority of Egyptian Christians are Copts. As of 2019, Copts in Egypt make up approximately 10 percent of the nation's population, with an estimated population of 9.5 million or 10 million. In 2018, approximately 90% of Egyptian Christians were Coptic Orthodox.

The history of Egyptian Christianity dates to the Roman era as Alexandria was an early center of Christianity.

The ministry of Jesus, in the canonical gospels, begins with his baptism near the River Jordan by John the Baptist, and ends in Jerusalem in Judea, following the Last Supper with his disciples. The Gospel of Luke states that Jesus was "about 30 years of age" at the start of his ministry. A chronology of Jesus typically sets the date of the start of his ministry at around AD 27–29 and the end in the range AD 30–36.

Jesus' early Galilean ministry begins when after his baptism, he goes back to Galilee from his temptation in the Judaean Desert. In this early period, he preaches around Galilee and recruits his first disciples who begin to travel with him and eventually form the core of the early Church as it is believed that the apostles dispersed from Jerusalem to found the apostolic sees. The major Galilean ministry which begins in Matthew 8 includes the commissioning of the Twelve Apostles, and covers most of the ministry of Jesus in Galilee. The final Galilean ministry begins after the beheading of John the Baptist as Jesus prepares to go to Jerusalem.

Paul, also named Saul of Tarsus, commonly known as Paul the Apostle or Saint Paul, was a Christian apostle (c. 5 – c. 64/65 AD) who spread the teachings of Jesus in the first-century AD. For his contributions towards the New Testament, he is generally regarded as one of the most important figures of the Apostolic Age, and he also founded several Christian communities in Asia Minor and Europe from the mid-40s to the mid-50s AD.

The main sources of information on Paul's life and works are Paul's letters and the Acts of the Apostles in the New Testament. Approximately half of its content documents his travels, preaching, and miracles. Paul was not one of the Twelve Apostles, and he did not know Jesus during his lifetime. Nonetheless, Paul was a contemporary of Jesus and personally knew eyewitnesses of Jesus such as his closest disciples (Peter and John) and brother James since the mid 30s AD, within a few years of the crucifixion (ca. 30–33 AD). He had knowledge of the life of Jesus and his teachings. According to the Acts, Paul lived as a Pharisee and participated in the persecution of early disciples of Jesus before his conversion. On his way to arrest Christians in Damascus, Paul saw a bright light, heard Christ speak, was blinded, and later healed by Ananias. After these events, Paul was baptized, beginning immediately to proclaim that Jesus of Nazareth was the Jewish messiah and the Son of God. He made three missionary journeys to spread the Christian message to non-Jewish communities.

The Patriarch of Alexandria is the archbishop of Alexandria, Egypt. Historically, this office has included the designation "pope" (etymologically "Father", like "Abbot").

The Alexandrian episcopate was revered as one of the three major episcopal sees (along with Rome and Antioch) before Constantinople and Jerusalem were granted similar status (in 381 and 451, respectively). Alexandria was elevated to de facto archiepiscopal status by the Councils of Alexandria, and this status was ratified by Canon Six of the First Council of Nicaea, which stipulated that all the Egyptian episcopal provinces were subject to the metropolitan see of Alexandria. In the sixth century, these five archbishops were formally granted the title of "patriarch" and were subsequently known as the Pentarchy.

In the 5th century in Christianity, there were many developments which led to further fracturing of the State church of the Roman Empire. Emperor Theodosius II called two synods in Ephesus, one in 431 and one in 449, that addressed the teachings of Patriarch of Constantinople Nestorius and similar teachings. Nestorius had taught that Christ's divine and human nature were distinct persons, and hence Mary was the mother of Christ but not the mother of God. The Council rejected Nestorius' view causing many churches, centered on the School of Edessa, to a Nestorian break with the imperial church. Persecuted within the Roman Empire, many Nestorians fled to Persia and joined the Sassanid Church (the future Church of the East) thereby making it a center of Nestorianism. By the end of the 5th century, the global Christian population was estimated at 10-11 million. In 451 the Council 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 themselves miaphysites. The resulting schism created a communion of churches, including the Armenian, Syrian, and Egyptian churches, that is today known as Oriental Orthodoxy. In spite of these schisms, however, the imperial church still came to represent the majority of Christians within the Roman Empire.

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 spoken vernacular. By the 5th century scholars in the West had begun to abandon Greek in favor of the use of Latin. The Church in Rome, in particular, began to encourage the use of Latin in the western provinces and published Jerome's Vulgate, the first authorized translation of the Bible in Latin.

Origen of Alexandria (c. 185 – c. 253), also known as Origen Adamantius, was an early Christian scholar, ascetic, and theologian who was born and spent the first half of his career in Alexandria. He was a prolific writer who wrote roughly 2,000 treatises in multiple branches of theology, including textual criticism, biblical exegesis and hermeneutics, homiletics, and spirituality. He was one of the most influential and controversial figures in early Christian theology, apologetics, and asceticism. He has been described by John Anthony McGuckin as "the greatest genius the early church ever produced".

Origen founded the Christian School of Caesarea, where he taught logic, cosmology, natural history, and theology, and became regarded by the churches of Palestine and Arabia as the ultimate authority on all matters of theology. He was tortured for his faith during the Decian persecution in 250 and died three to four years later from his injuries.

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.