Eastern Orthodox ChurchThe Eastern Orthodox Church, also called the Orthodox Church and officially the Orthodox Catholic Church, is the second-largest Christian church, with approximately 220 million baptized members. It operates as a communion of autocephalous churches, each governed by its bishops via local synods. The church has no central doctrinal or governmental authority analogous to the head of the Catholic Church—the pope—but the Ecumenical Patriarch of Constantinople is recognized by them as primus inter pares ("first among equals").
Catholic ChurchThe Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.3 billion baptized Catholics worldwide It is among the world's oldest and largest international institutions, and has played a prominent role in the history and development of Western civilization. The church consists of 24 sui iuris churches, including the Latin Church and 23 Eastern Catholic Churches, which comprise almost 3,500 dioceses and eparchies located around the world.
ChristologyIn Christianity, Christology (from the Greek Khristós and -logia), translated from Greek as 'the study of Christ', is a branch of theology that concerns Jesus. Different denominations have different opinions on questions such as whether Jesus was human, divine, or both, and as a messiah what his role would be in the freeing of the Jewish people from foreign rulers or in the prophesied Kingdom of God, and in the salvation from what would otherwise be the consequences of sin.
ArianismArianism (Ἀρειανισμός, Areianismós) is a Christological doctrine first attributed to Arius (AD 256–336), a Christian presbyter from Alexandria, Egypt. Arian theology holds that Jesus Christ is the Son of God, who was begotten by God the Father with the difference that the Son of God did not always exist but was begotten/made before "time" by God the Father; therefore, Jesus was not coeternal with God the Father, but nonetheless Jesus began to exist outside time as time applies only to the creations of God.
PopeThe pope (papa, from πάππας), also known as the supreme pontiff (pontifex maximus or summus pontifex), Roman pontiff (Romanus pontifex) or sovereign pontiff, is the bishop of Rome (or historically the patriarch of Rome), head of the worldwide Catholic Church, and has also served as the head of state or sovereign of the Papal States and later the Vatican City State since the eighth century.
ProtestantismProtestantism is a branch of Christianity that follows the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies. Protestantism emphasizes the Christian believer's justification by God in faith alone (sola fide) rather than by a combination of faith with good works as in Catholicism; the teaching that salvation comes by divine grace or "unmerited favor" only (sola gratia); the priesthood of all believers in the Church; and the sola scriptura ("scripture alone") that posits the Bible as the sole infallible source of authority for Christian faith and practice.
Christian denominationA Christian denomination is a distinct religious body within Christianity that comprises all church congregations of the same kind, identifiable by traits such as a name, particular history, organization, leadership, theological doctrine, worship style and, sometimes, a founder. It is a secular and neutral term, generally used to denote any established Christian church. Unlike a cult or sect, a denomination is usually seen as part of the Christian religious mainstream.
Council of ChalcedonThe Council of Chalcedon (kælˈsiːdən,_ˈkælsɪdɒn; Concilium Chalcedonense) was the fourth ecumenical council of the Christian Church. It was convoked by the Roman emperor Marcian. The council convened in the city of Chalcedon, Bithynia (modern-day Kadıköy, Istanbul, Turkey) from 8 October to 1 November 451 AD. The council was attended by over 520 bishops or their representatives, making it the largest and best-documented of the first seven ecumenical councils.
Chalcedonian DefinitionThe Chalcedonian Definition (also called the Chalcedonian Creed or the Definition of Chalcedon) is a declaration of Christ's nature (that it is dyophysite), adopted at the Council of Chalcedon in AD 451. Chalcedon was an early centre of Christianity located in Asia Minor. The council was the fourth of the ecumenical councils that are accepted by Chalcedonian churches which include the Catholic, Eastern Orthodox, Lutheran, Anglican and Reformed churches.
First Council of NicaeaThe First Council of Nicaea (naɪˈsi:ə ; Sýnodos tês Nīkaíās) was a council of Christian bishops convened in the Bithynian city of Nicaea (now İznik, Turkey) by the Roman Emperor Constantine I in AD 325. This ecumenical council was the first effort to attain consensus in the church through an assembly representing all Christendom. Hosius of Corduba may have presided over its deliberations.
