Byzantine Greeks or Byzantines (Greek: Βυζαντινοί) is a conventional term used by modern historians to refer to the medieval Greek or Hellenised citizens of the Byzantine Empire, centered mainly in Constantinople, the southern Balkans, the Greek islands, Asia Minor (modern Turkey), Cyprus and the large urban centres of the Near East and northern Egypt. The identity of the Byzantine Greeks has taken many forms in name, with such variants as Romaioi or Romioi (meaning "Romans"), Graikoi (meaning "Greeks"), "Byzantines", and "Byzantine Greeks".

The social structure of the Byzantine Greeks was primarily supported by a rural, agrarian base that consisted of the peasantry, and a small fraction of the poor. These peasants lived within three kinds of settlements, the chorion or village, the agridion or hamlet, and the proasteion or estate. Many civil disturbances that occurred during the time of the Byzantine Empire were attributed to political factions within the Empire rather than to this large popular base. Soldiers among the Byzantine Greeks were at first conscripted amongst the rural peasants and trained on an annual basis. As the Byzantine Empire entered the 11th century, more of the soldiers within the army were either professional men-at-arms or mercenaries.

The Greeks, also known as the Hellenes (Greek: Ἕλληνες, [ˈelines]), are a nation and ethnic group native to Greece, Cyprus and other regions. They also form a significant diaspora, with Greek communities established around the world.

Greek colonies and communities have been historically established in most corners of the Mediterranean, but Greeks have always been centered around the Aegean Sea, where the Greek language has been spoken since antiquity. Until the early 20th century, Greeks were uniformly distributed between the Greek peninsula, the western coast of Asia Minor, Pontus, Egypt, Cyprus and Constantinople; many of these regions coincided to a large extent with the borders of the Byzantine Empire of the late 11th century and the Eastern Mediterranean areas of the ancient Greek colonization.

In the aftermath of the Greco-Turkish War (1919–1922), a large-scale population exchange between Greece and Turkey transferred and confined Christians from Turkey, except Constantinople (effectively ethnic Greeks) into the borders of the modern Greek state and Cyprus. Other ethnic Greek populations can be found from southern Italy to the Caucasus and in diaspora communities in a number of other countries. Today, most Greeks are officially registered as members of the Greek Orthodox Church.

The Greek is a fictional character on the HBO drama The Wire, played by actor Bill Raymond. The Greek is the head of an international criminal organization involved in narcotics and human trafficking. The Greek is a mysterious figure involved in numerous criminal activities. His given name is never mentioned on the show, and though he is known only as "The Greek", he has stated (in the episode Port in a Storm) that he is not actually Greek. A quiet and unassuming man, the Greek prefers to keep a low profile, operating all of his business through his lieutenant Spiros "Vondas" Vondopoulos. His smuggling organization operated from a small diner in Baltimore for years, and while Vondas would conduct business the Greek would listen in quietly at the counter. Nick Sobotka, upon seeing the Greek identify himself, was amazed that the shadowy figure had been in plain sight the entire time.

Despite his calm appearance, the Greek is cunning and ruthless, and only interested in facts that make him more money. Series creator David Simon has said that The Greek is an embodiment of raw unencumbered capitalism. Anyone interfering in this process is eliminated immediately, and he prefers to leave victims headless and handless to hinder identification.

Saints Cyril and Methodius (Greek: Κύριλλος καὶ Μεθόδιος, Old Church Slavonic: Кѷриллъ и Меѳодїи) were Byzantine Greek brothers born in Thessaloniki in the 9th century. They were Christian missionaries among the Slavic peoples of the First Bulgarian Empire, Great Moravia, and Pannonia. Through their work they influenced the cultural development of all Slavs, for which they received the title "Apostles to the Slavs". They are credited with devising the Glagolitic alphabet, the first alphabet used to transcribe Old Church Slavonic. After their deaths, their pupils continued their missionary work among other Slavs. Both brothers are venerated in the Orthodox Church as saints with the title of "equal-to-apostles". In 1880, Pope Leo XIII introduced their feast into the calendar of the Roman Catholic Church. In 1980, Pope John Paul II declared them co-patron saints of Europe, together with Benedict of Nursia.

The two brothers were born in Thessaloniki – Cyril in 827–828 and Methodius in 815–820. Cyril was reputedly the youngest of seven brothers; he was born Constantine, but took the name Cyril upon becoming a monk shortly before his death, according to the "Vita Cyrilli" ("The Life of Cyril"). Their father was Leo, a droungarios of the Byzantine theme of Thessaloniki, and their mother was Maria, who may have been a Slav.

John Chrysostom (c. 347–407, Greek: Ἰωάννης ὁ Χρυσόστομος), Archbishop of Constantinople, was an important Early Church Father. He is known for his eloquence in preaching and public speaking, his denunciation of abuse of authority by both ecclesiastical and political leaders, the Divine Liturgy of St. John Chrysostom, and his ascetic sensibilities. After his death in 407 (or, according to some sources, during his life) he was given the Greek epithet chrysostomos, meaning "golden mouthed" in English, and Anglicized to Chrysostom.

The Orthodox and Eastern Catholic Churches honor him as a saint and count him among the Three Holy Hierarchs, together with Basil the Great and Gregory Nazianzus. He is recognized by the Eastern Orthodox Church and the Catholic Church as a saint and as a Doctor of the Church. Churches of the Western tradition, including the Roman Catholic Church, some Anglican provinces, and parts of the Lutheran Church, commemorate him on 13 September. Some Lutheran and many Anglican provinces commemorate him on the traditional Eastern feast day of 27 January. The Coptic Orthodox Church of Alexandria also recognizes John Chrysostom as a saint (with feast days on 16 Thout and 17 Hathor).