Eastern Orthodox Church

=== Early Church ===

[[File:Ephesus IchthysCrop.jpg|thumb|An early Christian "[[Ichthys]]" (''fish'') inscription from ancient [[Ephesus]]|210x210px]]

[[Paul of Tarsus|Paul]] and the [[Twelve Apostles|Apostles]] travelled extensively throughout the [[Roman Empire]], including Asia Minor, [[Early Christianity|establishing churches in major communities]], with the first churches appearing in [[Jerusalem in Christianity|Jerusalem]] and the [[Holy Land]], then in [[Antioch]], [[Ethiopia]], [[Egypt]], [[Rome]], [[Alexandria]], [[Athens]], [[Thessalonica]], [[Illyricum (Roman province)|Illyricum]], and [[Constantinople|Byzantium]], which centuries later would become prominent as the [[New Rome]].<ref name=ware1993>{{harvnb|Ware|1993}}</ref> Christianity [[Persecution of Christians in the Roman Empire|encountered considerable resistance in the Roman Empire]], mostly because its adherents refused to comply with the demands of the Roman state—often even when their lives were threatened—by offering sacrifices to the pagan gods. Despite persecution, skepticism, and initial social stigma, the Christian Church spread, particularly following the [[Constantine I and Christianity|conversion of Emperor Constantine I]] in AD 312.<ref name=ware1993/>

By the [[Christianity in the 4th century|fourth century]], Christianity was present in numerous regions well beyond the Levant. A number of influential schools of thought had arisen, particularly the [[Catechetical School of Alexandria|Alexandrian]] and [[School of Antioch|Antiochian]] philosophical approaches. Other groups, such as the [[Arians]], had also managed to gain influence. However, their positions caused theological conflicts within the church, thus prompting the [[Constantine the Great|Emperor Constantine]] to call for a great ecumenical synod in order to define the church's position against the growing, often widely diverging, philosophical and theological interpretations of Christianity. He made it possible for this council to meet not only by providing a location, but by offering to pay for the transportation of all the existing bishops of the church. Most modern Christian churches regard this synod, commonly called the [[First Council of Nicaea]] or more generally the [[First Ecumenical Council]],<ref name=ware1993/><ref>{{cite book| author = Tomáš Špidlík
| title = The spirituality of the Christian East: a systematic handbook| year = 1986
| isbn = 978-0-87907-879-9 }}</ref> as of major importance.