Christianity first spread in the predominantly
Greek-speaking eastern half of the
Roman Empire. The
Apostles traveled extensively throughout the empire, establishing communities in major cities and regions, with the first community appearing in
Jerusalem, followed by communities in
Ethiopia and others. Early growth also occurred in the two political centers of
Greece, as well as in
Byzantium (initially a minor centre under the Metropolitan of Heraclea, but which later became
Constantinople). Orthodoxy believes in the
apostolic succession that they believe was established by the Apostles in the
New Testament; this played a key role in the communities' view of itself as the preserver of the original Christian tradition. Historically the word
"church" did not mean a building or housing structure (for which Greek-speakers might have used the word "
basilica") but meant a community or gathering of like peoples (see
ekklesia). The earliest
Ecclesiology would posit that the
Eucharistic assembly, under the authority and permission of a
Bishop, is what constitutes a Church. As St.
Ignatius of Antioch said, "Let no man do anything connected with the Church without the bishop. Let that be deemed a proper Eucharist, which is [administered] either by the bishop, or
by one to whom he has entrusted it. Wherever the bishop shall appear, there let the multitude [of the people] also be; even as, wherever Jesus Christ is, there is
the Catholic Church. It is not lawful without the bishop either to baptize or to celebrate
The original church or community of the East before the
Great Schism comprised:
The church of Rome by tradition was founded by both Saint Peter and Saint Paul.
persecution of the early Christian church caused it to become an underground movement. The first above-ground legal churches were built in
Echmiadzin). Armenia became the first country to legalize Christianity (around 301
King Tiridates III and also embrace it as the state religion in 310 AD. However, illegal churches before "Christian legalization" are mentioned throughout church history; for example, in the City of
Nisibis during the persecutions of
Diocletian. Of the underground churches that existed before legalization, some are recorded to have existed in the
catacombs of Europe i.e.
Catacombs of Rome and also in Greece (see
Cave of the Apocalypse,
The Church of St George and the church at
Pergamon) and also in the
underground cities of
Anatolia such as
Derinkuyu Underground City (also see
Cave monastery and
Bab Kisan). Also noteworthy are the
Church of St Peter in Antioch and the
Cenacle in Jerusalem.
Much of the official organizing of the
ecclesiastical structure, clarifying true from false teachings was done by the bishops of the church. Their works are referred to as
Patristics. This tradition of clarification can be seen as established in the saints of the Orthodox Church referred to as the
Apostolic Fathers, bishops themselves established by
apostolic succession. This also continued into the age when the practice of the religion of Christianity became legal (see the Ecumenical Councils).
Biblical canon began with the officially accepted books of the
Old Testament (which predates Christianity). This canon, called the
Septuagint or seventy, continues to be the Old Testament of the Orthodox faith, along with the
Good news (gospels),
Revelations and Letters of the Apostles (including
Acts of the Apostles and the
Epistle to the Hebrews). The earliest text of the
New Testament was written in common or Koine Greek. The texts of the Old Testament had previously been translated into a single language, Koine Greek, in the time of
Ptolemy II Philadelphus in 200 BC.
The early Christians had no way to have a copy of the works that later became the canon and other church works accepted but not canonized. Much of the original church
liturgical services functioned as a means of learning these works. Orthodox Church services today continue to serve this educational function. The issue of collecting the various works of the eastern churches and compiling them into a canon, each being confirmed as authentic text was a long protracted process. Much of this process was motivated by a need to address various heresies. In many instances, heretical groups had themselves begun compiling and disseminating text that they used to validate their positions, positions that were not consistent with the text, history and traditions of the Orthodox faith.
Liturgical services, especially the
Eucharist service, are based on repeating the actions of Jesus ("do this in remembrance of me"), using the bread and wine, and saying his words (known as the words of the institution). The church has the rest of the liturgical ritual being rooted in Jewish
synagogue services, including the singing of
hymns (especially the
Psalms) and reading from the Scriptures (
New Testament). The final uniformity of liturgical services became solidified after the church established a
Biblical canon, being based on the
Apostolic Constitutions and
In the Orthodox view, the Bible represents those texts approved by the church for the purpose of conveying the most important parts of what it already believed. The oldest list of books for the canon is the
Muratorian fragment dating to ca. 170 (see also
Chester Beatty Papyri). The oldest complete canon of the Christian Bible was found at
Saint Catherine's Monastery (see
Codex Sinaiticus) and later sold to the British by the Soviets in 1933.
 Parts of the codex are still considered stolen by the Monastery even today.
 These texts (as a whole) were not universally considered canonical until the church reviewed, edited, accepted and ratified them in 368 AD (also see the
Soteriology from the Orthodox perspective is achieved not by knowledge of scripture but by being a member of the church or community and cultivating
theosis through participation in the church or community.