Ecumenical Patriarchate of Constantinople in the context of "Eastern Orthodox"

A Greek Orthodox Church (Greek: Ἑλληνορθόδοξη Ἐκκλησία, romanized: Ellinorthódoxi Ekklisía, IPA: [elinorˈθoðoksi ekliˈsia]) is any of three classes of Christian churches, each associated in some way with Greek Christianity, Levantine Arabic-speaking Christians or more broadly the rite used in the Eastern Roman Empire:

• The broader meaning refers to "the entire body of Orthodox (Chalcedonian) Christianity, sometimes also called 'Eastern Orthodox', 'Greek Catholic', or generally 'the Greek Church'".
• A second, narrower meaning refers to "any of several independent churches within the worldwide communion of [Eastern] Orthodox Christianity that retain the use of the Greek language in formal ecclesiastical settings". In this sense, the Greek Orthodox Churches are the Ecumenical Patriarchate of Constantinople and its dependencies, the Patriarchates of Alexandria, Antioch and Jerusalem, the Church of Greece and the Church of Cyprus.
• The third meaning refers to the Church of Greece, an Eastern Orthodox Church operating within the modern borders of Greece.

Constantinople (see other names) was a historical city located on the Bosporus that served as the capital of the Roman (including its eastern continuation), Latin, and Ottoman empires between its consecration in 330 and the formal abolishment of the Ottoman sultanate in 1922. Initially, as New Rome, Constantinople was founded in 324 during the reign of Constantine the Great on the site of the existing settlement of Byzantium and in 330 became the capital of the Roman Empire. Following the collapse of the Western Roman Empire in the late 5th century, Constantinople remained the capital of the Eastern Roman Empire (also known as the Byzantine Empire; 330–1204 and 1261–1453), the Latin Empire (1204–1261), and the Ottoman Empire (1453–1922). In the aftermath of the Turkish War of Independence, the Turkish capital moved to Ankara. Although the city had been known as Istanbul since 1453, it was officially renamed Istanbul on 28 March 1930. As of October 2025, it is the most populous city in Europe, with a population of more than 16 million residents, straddling the Bosporus Strait and lying in both Europe and Asia, and is the financial center of Turkey.

In 324, following the reunification of the Eastern and Western Roman Empires, the ancient city of Byzantium was selected to serve as the new capital of the Roman Empire, and the city was renamed Nova Roma, or 'New Rome', by Emperor Constantine the Great. On 11 May 330, it was renamed Constantinople and dedicated to Constantine. Shortly afterward, in 474 AD, the Great Fire of Constantinople erupted and consequently devastated the region. Constantinople is generally considered to be the center and the "cradle of Orthodox Christian civilization." From the mid-5th century to the early 13th century, Constantinople was the largest and wealthiest city in Europe. The city became famous for its architectural masterpieces, such as Hagia Sophia, the cathedral of the Eastern Orthodox Church, which served as the seat of the Ecumenical Patriarchate; the sacred Imperial Palace, where the emperors lived; the Hippodrome; the Golden Gate of the Land Walls; and opulent aristocratic palaces. The University of Constantinople was founded in the 5th century and contained artistic and literary treasures before it was sacked in 1204 and 1453, including its vast Imperial Library. which contained more than 100,000 volumes. The city was the home of the Ecumenical Patriarch of Constantinople and guardian of Christendom's holiest relics, such as the Crown of Thorns and the True Cross.

Serbia, officially the Republic of Serbia, is a landlocked country in Southeast and Central Europe. Located in the Balkans, it borders Hungary to the north, Romania to the northeast, Bulgaria to the southeast, North Macedonia to the south, Croatia to the northwest, Bosnia and Herzegovina to the west, and Montenegro to the southwest. Serbia also claims to share a border with Albania through the disputed territory of Kosovo. Serbia has about 6.6 million inhabitants, excluding Kosovo. Serbia's capital, Belgrade, is also the largest city in the country.

Continuously inhabited since the Paleolithic age, the territory of modern-day Serbia faced Slavic migrations in the 6th century. Several regional states were founded in the Early Middle Ages and were at times recognised as tributaries to the Byzantine, Frankish and Hungarian kingdoms. The Serbian Kingdom obtained recognition by the Holy See and Constantinople in 1217, reaching its territorial apex in 1346 as the Serbian Empire. By the mid-16th century, the Ottoman Empire annexed the entirety of modern-day Serbia; their rule was at times interrupted by the Habsburg Empire, which began expanding towards Central Serbia from the end of the 17th century while maintaining a foothold in Vojvodina. In the early 19th century, the Serbian Revolution established the nation-state as the region's first constitutional monarchy, which subsequently expanded its territory.

Eastern Orthodoxy, otherwise known as Eastern Orthodox Christianity or Byzantine Christianity, is one of the three main branches of Chalcedonian Christianity, alongside Catholicism and Protestantism. Like the Pentarchy of the first millennium, the mainstream (or "canonical") Eastern Orthodox Church is organised into autocephalous churches independent from each other. In the 21st century, the number of mainstream autocephalous churches is seventeen; there also exist autocephalous churches unrecognized by those mainstream ones. Autocephalous churches choose their own primate. Autocephalous churches can have jurisdiction (authority) over other churches, some of which have the status of "autonomous" which means they have more autonomy than simple eparchies.

Many of these jurisdictions correspond to the territories of one or more modern states; the Patriarchate of Moscow, for example, corresponds to Russia and some of the other post-Soviet states. They can also include metropolises, bishoprics, parishes, monasteries, or outlying metochia corresponding to diasporas that can also be located outside the country where the primate resides (e.g., the case of the Ecumenical Patriarchate of Constantinople whose canonical territory is located partly in northern Greece and the east); sometimes they overlap (the case of Moldova where the jurisdictions of the patriarchs of Bucharest and of Moscow overlap).

The Greek Orthodox Patriarchate of Alexandria and all Africa (Ancient Greek: Πατριαρχεῖον Ἀλεξανδρείας καὶ πάσης Ἀφρικῆς, romanized: Patriarkheîon Alexandreías ke pásīs Afrikês, lit. 'The Patriarchate of Alexandria and all Africa'), also known as the Greek Orthodox Church of Alexandria, is an autocephalous patriarchate that is part of the Eastern Orthodox Church. Its seat is in Alexandria, and it has canonical responsibility for the entire African continent.

It is commonly called the Greek or Eastern Orthodox Patriarchate of Alexandria to distinguish it from the Coptic Orthodox Patriarchate of Alexandria. Members of the Greek Orthodox Patriarchate were once referred to as "Melkites" by non-Chalcedonian Christians because they remained in communion with the Ecumenical Patriarchate of Constantinople after the schism that followed the Council of Chalcedon in 451. Mark the Evangelist is considered the founder of the See, and the Patriarchate's emblem is the Lion of Saint Mark.

The Church of Greece (Greek: Ἐκκλησία τῆς Ἑλλάδος, romanized: Ekklēsía tē̂s Helládos, IPA: [ekliˈsi.a tis eˈlaðos]), part of the wider Greek Orthodox Church, is one of the autocephalous churches which make up the communion of Eastern Orthodox Christianity. Its canonical territory is confined to the borders of Greece prior to the Balkan Wars of 1912–1913 ("Old Greece"), with the rest of Greece (the "New Lands", Crete, and the Dodecanese) being subject to the jurisdiction of the Ecumenical Patriarchate of Constantinople. However, most of the dioceses of the Metropolises of the New Lands are de facto administered as part of the Church of Greece for practical reasons, under an agreement between the churches of Athens and Constantinople. The primate of the Church of Greece is the archbishop of Athens and All Greece.

The Ecumenical Patriarch of Constantinople (Greek: Οἰκουμενικός Πατριάρχης, romanized: Oikoumenikós Patriárchēs) is the archbishop of Constantinople and primus inter pares (first among equals) among the heads of the several autocephalous churches that comprise the Eastern Orthodox Church. The ecumenical patriarch is regarded as the representative and spiritual leader of the Eastern Orthodox Christians worldwide. The term ecumenical in the title is a historical reference to the Ecumene, a Greek designation for the civilised world, i.e. the Roman Empire, and it stems from Canon 28 of the Council of Chalcedon.

The patriarch's see, the Ecumenical Patriarchate of Constantinople, is one of the most enduring institutions in the world and has had a prominent part in world history. The ecumenical patriarchs in ancient times helped in the spread of Christianity and the resolution of various doctrinal disputes. In the Middle Ages, they played a major role in the affairs of the Eastern Orthodox Church, as well as in the politics of the Orthodox world, and in spreading Christianity among the Slavs. Currently, in addition to the expansion of the Christian faith and the Eastern Orthodox doctrine, the patriarchs are involved in ecumenism and interfaith dialogue, charitable work, and the defense of Orthodox Christian traditions.

The 2018 Moscow–Constantinople schism is an ongoing schism between the Russian Orthodox Church (ROC, also known as the Moscow Patriarchate) and the Ecumenical Patriarchate of Constantinople, which began on 15 October 2018 when the former unilaterally severed full communion with the latter.

The resolution was taken in response to a decision of the Holy Synod of the Ecumenical Patriarchate of Constantinople of 11 October 2018, confirming its intentions to grant autocephaly to the Orthodox Church of Ukraine in the future. The decision also stated that the Holy Synod would immediately: reestablish a stauropegion in Kyiv, i.e. a church body subordinated directly to the ecumenical patriarch; revoke the "Letter of issue" (permission) of 1686 that had given permission to the patriarch of Moscow to ordain the metropolitan of Kiev and lift the excommunications which affected the clergy and faithfuls of two unrecognized Ukrainian Eastern Orthodox churches. Those two unrecognized churches, the Ukrainian Autocephalous Orthodox Church (UAOC) and the Ukrainian Orthodox Church – Kyiv Patriarchate (UOC-KP), were competing with the Ukrainian Orthodox Church (Moscow Patriarchate) (UOC-MP) and were considered "schismatics" (illegally segregated groups) by the Patriarchate of Moscow, as well as by the other Eastern Orthodox churches.

Patriarchate (/ˈpeɪtriɑːrkɪt, -keɪt/, UK also /ˈpætri-/; Ancient Greek: πατριαρχεῖον, patriarcheîon) is an ecclesiological term in Christianity, referring to the office and jurisdiction of a patriarch.

According to Christian tradition, three patriarchates—Rome, Antioch, and Alexandria—were established by the apostles as apostolic sees in the 1st century. These were officially recognized by the First Council of Nicaea. The Patriarchate of Constantinople was added in the 4th century, and the Patriarchate of Jerusalem followed in the 5th century. These five sees were later recognized collectively as the pentarchy by the Council of Chalcedon in 451.