Alexander was born in 1405 as the second son of
Alexios IV Megas Komnenos, who ruled the
Empire of Trebizond from 1417 to 1429. He had two brothers; the elder
John and the younger
David, and at least three sisters, one of whom was
Maria, who married the
Byzantine emperor John VIII Palaiologos (1425–1448). In the writings of contemporary historian
Laonikos Chalkokondyles, Alexander is called Skantarios, a name seemingly of Turkish origin, perhaps related to İskender, the Turkish form of Alexander.
George Finlay suggested in 1851 that Alexander was called Skantarios by his contemporaries and that this indicated Turkish influence in the Greek dialect of Trebizond. Certain modern scholars, such as Michel Kuršanskis, as well as the
Prosopographisches Lexikon der Palaiologenzeit, favor using the name Skantarios rather than Alexander. As the eldest son, Alexios had initially made Alexander's brother John the designated heir, and possibly associated him with imperial power as co-emperor. Relations between Alexios IV and John deteriorated throughout Alexios's reign, owing to John's ambition and to Alexios being seen as a weak ruler. The familial issues reached a breaking point 1426, when John discovered that his mother (Alexios's wife)
Theodora Kantakouzene was having an affair with the
treasurer. John murdered the man with his own hands and then launched a
palace coup, imprisoning his parents in their respective apartments in the imperial palace. Worried that John was planning to kill both of them, the Trapezuntine nobility persuaded the populace that John would make a worse ruler than Alexios, and forced him to flee the city, before releasing Alexios and Theodora. John fled to
Georgia, where he married a daughter of King
Alexander I (1412–1442). After John's rebellion, Alexios appears to have designated his next eldest son, Alexander, as heir instead, and perhaps made him co-emperor. John made plans to conquer Trebizond while in exile. From Georgia, he travelled to
Crimea, and tried to organize an expedition against Alexios with the help of the
Genoese. In the meantime, Alexios IV worked to seal alliances to ensure the safety of his empire. He appears to have negotiated with Prince
Alexios of Theodoro to marry either Alexander or David to Alexios's daughter,
Maria of Gothia. Any negotiations fell through when John and the Genoese landed at the port of
Cordyle in early 1429. Alexios left Trebizond to march against John, but some among the Trapezuntine nobility changed their allegiance to John and on 26 April 1429, Alexios was assassinated in his tent during the night, after which John became emperor as John IV. After the assassination of Alexios and the accession of John, Alexander was exiled, fleeing to
Constantinople, where he lived with his sister Maria. == Life in exile ==