Alexios IV Megas Komnenos or Alexius IV (Greek: Αλέξιος Δ΄ Μέγας Κομνηνός, Alexios IV Megas Komnēnos), (1382–1429), Emperor of Trebizond from March 5, 1417 to October 1429. He was the son of Emperor Manuel III and Gulkhan-Eudokia of Georgia.
Alexios IV had been associated in authority and given the title of despotes by his father as early as 1395. Nevertheless, the two quarreled as Alexios was impatient to assume supreme power; William Miller compared this to «the first three sovereigns of the House of Hanover» for whom «the heir-apparent always quarrelled with his father.» When his father died in 1417, Alexios was accused by some of having expedited his death. Alexios inherited a conflict with the Genoese, who defeated the fleet of Trebizond and seized a local monastery, which they converted into a fortress. By 1418 he had signed a peace agreement and paid reparations to the Genoese until 1422. A new dispute arose over the emperor’s obligations in 1425 and was not resolved until 1428. Relations with the Republic of Venice were generally better.
After the death of Tamerlane, most of Asia Minor descended into chaos. Kara Yusuf, ruler of the Kara Koyunlu or «Black Sheep» Turks, devastated much of Armenia and defeated the Emir of Arsinga and the chieftain of the Ak Koyunlu or White Sheep Turks. Alexios sought to avoid hostility by marrying off daughters to his powerful Muslim neighbors. One daughter was married to Kara Yusuf’s son Jihan Shah(Jahanshah) in c.1420, and Alexios agreed to pay his son-in-law the same amount of tribute that had previously been due to Tamerlane. Another daughter was possibly married to Ali, son of Kara Yülük Osman, the ruler of Ak Koyunlu, though Osman himself was likely the groom.
Alexios’ marital policy also extended to his Christian neighbors, and his daughter Maria of Trebizond was married off to the Byzantine Emperor John VIII Palaiologos in 1428. Her sister Eudokia had married Niccolò Crispo, the Italian lord of Syros — they became the biological grandparents of Catherine Cornaro, Queen of Cyprus.
According to George Finlay, Alexios IV spent much of his time in pursuit of pleasure and accomplished relatively little, although there is no evidence in contemporary sources for this claim. Following tradition, he granted his eldest son, John IV, the courtly title of despotes in 1417. Despite this, relations deteriorated between father and son, and in 1426 John murdered Alexios’ Treasurer, alleging an affair between him and the Empress Theodora Kantakouzene. He also attempted to eliminate his parents, but the nobles intervened and prevented the attempt and John fled to Georgia.
When Alexios IV’s wife Theodora died in 1426, he was so distraught that Bessarion wrote him no less than three monodias, which help to shed some light on this otherwise dark period lacking in sources.
Due to John’s disloyalty and usurpation, Alexios IV made his younger son Alexander of Trebizond despotes and married him to Maria Gattilusio, a daughter of Dorino of Lesbos. Eventually John left Georgia for the Genoese colony at Caffa, where he enlisted a galley and its crew to help him recover his position in Trebizond. Alexios IV marched out to resist his son, but was murdered during the night by nobles who had been won over by John, sometime in October 1429. According to our source for the period Laonicus Chalcondyles, Alexander fled either to his father-in-law Dorino of Lesbos, or to Constantinople. ….