Alexius IV(Alexius Angelus), d. 1204, Byzantine emperor (1203–4), son of Isaac IIIsaac II
(Isaac Angelus) , d. 1204, Byzantine emperor (1185–95, 1203–4). The great-grandson of Alexius I, he was proclaimed emperor by the mob that had killed the unpopular Andronicus I.
..... Click the link for more information. . When his father was deposed, Alexius fled to Italy and then went to Germany. Encouraged by his brother-in-law, Philip of Swabia, he obtained (1202) from the leaders of the Fourth Crusade (see CrusadesCrusades
, series of wars undertaken by European Christians between the 11th and 14th cent. to recover the Holy Land from the Muslims. First Crusade
In the 7th cent., Jerusalem was taken by the caliph Umar.
..... Click the link for more information. ) the promise of help in deposing his uncle, Alexius III. Made joint emperor with Isaac II after the Crusaders entered Constantinople, he was overthrown for his subservience to his allies and was strangled by order of Alexius V.