Job: Monk who lived in the second half of the 13th century and wrote a Life of St Theodora of Arta, as well as hymns for the Nativity, Epiphany and Pentecost. He is said to appear in the History of George Pachymeres, under the name of Job Iasites or Iasites Melias. He was also an adviser of patriarch Joseph I and the author of an anti-Unionist work. Because of his opposition to the Union, he was exiled to Bithynia in 1275.
John Alexander: Bulgarian tsar (1331-71).
John Anagnostes: Writer of the early 15th century. Anagnostes was probably not his surname, but rather refers to his task and clerical rank of reader. We know nothing of his life, apart from the fact that he lived in Thessalonike during the siege of the sultan Murad II in 1430 and wrote a Diegesis (short narrative) of the events as an eyewitness.
John Asen II: Bulgarian tsar (1218-41). Firstborn son of Asen I and one of the founders of the 2nd Bulgarian empire.
John Doukas: Brother of Manuel Angelos and his successor as ruler of Thessalonike (1237-42).
John I Doukas Angelos: Sebastokrator of Thessaly (1267/8-1289) after the distribution of the land of Epiros by his father Michael II. In spite of the efforts of Michael VIII Palaiologos, he would not submit to the authority of Byzantium, and his relations with Constantinople continued to be strained during the time of Andronikos II Palaiologos.
John III Vatatzes: Emperor of the state of Nicaea from 1222 to 1254. After his death he was canonised by the Greeks of Asia Minor.
John IV Laskaris: Byzantine emperor (1258-61). Son and successor of Theodore II Laskaris. Michael VIII Palaiologos usurped John's rights to the throne and blinded him in 1261. He died in prison around 1305.
John Ugljesa: Serb despotes from around 1366 to 1371.
John V Palaiologos: Byzantine emperor (1341-91) and son of the emperor Andronikos III Palaiologos and Anna of Savoy.
John VI Kantakouzenos: Emperor of Byzantium (1347-54). After his abdication, he became a monk under the name of Ioasaph and devoted himself to the writing of various works, among which is his Historiai, covering the period between 1320 and 1356. He died at Mistra, where his son, Manuel, was made despotes in 1383.
John VII Palaiologos: Byzantine emperor (1390) and son of Andronikos IV Palaiologos. From 1399 to 1402 he acted as regent for Manuel II during the latter's sojourn in the West. He died in 1408 as monk Ioasaph.
John VIII Palaiologos: Byzantine emperor (1425-48). Protagonist of the union of the Churches at Ferrara-Florence in 1439.
John XI Bekkos: Patriarch of Constantinople (1275/6-1282), he was at first an opponent of the union of the Churches but later became the leader of the Unionists. As patriarch he tried to implement the Union of Lyons, arousing great opposition from all sides. He supported the emperor Michael VIII, but after the latter's death he was deposed from the patriarchal throne and was exiled when Andronikos II restored Orthodoxy in 1282. In 1285 he was charged with heresy and condemned by the anti-Unionists at the Council of Blachernai.
John XIV Kalekas: Patriarch of Constantinople (1334-47) and member of the regency during the civil war with Kantakouzenos. During his patriarchate various important documents were issued.
Joseph I: Patriarch of Constantinople (1266-75 and 1282-83). He was against the union of the Churches in 1274 and was forced to resign from his office. He was replaced by Andronikos II in 1282. He died a year later and was canonised for his anti-unionist stand. His feast day is celebrated on 30 October.
Joseph II: Metropolitan of Ephesus and Patriarch of Constantinople (1416-1439). Illegitimate son of the last tsar of Bulgaria, John II Sisman. A pro-Unionist, he played a leading role at the Council of Ferrara-Florence, during which he died, and was buried at the church of Santa Maria Novella in Florence.
Joseph Rhakendytes ("wearer of rags")(1260 or 1280 ca.1330): Learned monk and physician also known as Joseph the Philosopher. He was a member of a group of scholars at the court of Andronikos II, and had wide-ranging interests, which included philosophy, medicine, rhetoric, mathematics, astronomy and theology.
Justinian I: Emperor of Byzantium (527-565), he instituted a number of reforms and was responsible for an extensive programme of building and restoration, which included the great church of Hagia Sophia in Constantinople. Thanks to his military expeditions he managed to restore the Byzantine empire to the area it had covered in earlier Roman times. Portraits of his survive in the mosaic decorations of Hagia Sophia and in Ravenna, Italy.