1911 Encyclopædia Britannica/John Angelus

JOHN ANGELUS (d. 1244), emperor of Thessalonica. In 1232 he received the throne from his father Theodore, who, after a period of exile, had re-established his authority, but owing to his loss of eyesight resolved to make John the nominal sovereign. His reign is chiefly marked by the aggressions of the rival emperor of Nicaea, John Vatatzes, who laid siege to Thessalonica in 1243 and only withdrew upon John Angelus consenting to exchange the title “emperor” for the subordinate one of “despot.”

See G. Finlay, History of Greece, vol. iii. (1877).