or ALE'XIUS IV. A'NGELUS (Ἄλεξις or Ἀλέξιος Ἄγγελος), was the son of the emperor Isaac II. Angelus. It is mentioned under ALEXIS III. that, after the deposition of this emperor, he and his father were placed on the throne by the Crusaders. Alexis IV. was crowned together with Isaac II. on the 29th of July, 1203, and, to secure himself on the throne, engaged the Crusaders to continue at Constantinople. He had promised them to put an end to the schism of the Greek Church, but did not do anything for that purpose, nor did he fulfil his other engagements towards the Crusaders. At the same time, he did not understand how to maintain his dignity among the turbulent and haughty barons of Italy, France, and Flanders, who were assembled in his capital. Serious differences consequently arose between him and his deliverers. Alexis Ducas, surnamed Murzuphlus, an ambitious and enterprising man, took advantage of these troubles, and suddenly seized the crown. By his order Alexis IV. was put to death on the 28th of January, 1204; Isaac II. died of grief. (Nicetas, Isaacius Angelus, 3.c. 8, &c.; Isaacius et Alexis fil.; Villehardouin, Ibid. c. 51, 56, 60, &c., 102-107.)