1448 Death of Joannes. His brother Constantine (XIII) Palæologus or Dragazes, despot of Sparta, succeeds.
1449 Muhammed II succeeds Murad II. His chief ambition is the conquest of Constantinople, and he at once prepares for it. Builds a fort on the Bosporus.
1452 Joannes appeals to Pope Nicholas V for aid. Cardinal Isidore and a small body of auxiliaries are sent.
1453 Siege and capture of Constantinople by Muhammed II. Death of Constantine in battle. Muhammed enters his new capital. End of the Eastern Empire.
THE EMPIRE OF TREBIZOND (1204-1461 A.D.)
Isaac Angelus, as soon as he is placed on the throne by the exasperated mob that slew the tyrannical Andronicus I (1185), has the eyes of Manuel Comnenus, the murdered emperor’s eldest son, put out. Manuel dies under the operation, leaving two sons, Alexius and David. They live in obscurity in Constantinople until the crusaders besiege the capital (1203), when they escape to the coast of Colchis. Alexius gathers around him a small force and 1204 about the time of the fall of Constantinople enters Trebizond, the ancient Trapezus, on the Black Sea, having been proclaimed “emperor of the Romans.” He calls himself Alexius (I) Grand-Comnenus, to distinguish himself from the family of Alexius Angelus-Comnenus. The weakness of the expelled house of Angelus permits Alexius to found his empire and begin a career of conquest. In the course of a few months the whole country from the Phasis to the Thermodon is his. David Comnenus adds the coast from Sinope to Heraclea to the new empire.
1206 Defeat of David on the Sangarius, by Theodore (I) Lascaris. Alexius badly beaten at Amisus by the sultan of Iconium or Rum in league with Theodore. David makes treaty with the emperor Henry of Romania, in the interest of his possessions.
1214 Theodore I attempts to reunite David’s territory to the empire of Nicæa. Death of David in defence of Sinope, besieged and captured by the Turks. Pontus assailed by the Turks. Colchis by the Georgians.
1216 Alexius compelled to declare himself a vassal of the sultan of Iconium.
1222 Death of Alexius. His son-in-law, Andronicus (I) Ghidus, succeeds, Joannes the eldest son being passed over.