(Βαλδουῗνος), BALDWIN, the first Latin emperor of Constantinople, was the son of Baldwin, count of Hainaut, and Marguerite, countess of Flanders. He was born at Valenciennes in 1171, and after the death of his parents inherited both the counties of Hainaut and Flanders. He was one of the most powerful among those warlike barons who took the cross in 1200, and arrived at Venice in 1202, whence they intended to sail to the Holy Land. They changed their plan at the supplication of prince Alexis Angelus, the son of the emperor Isaac II. Angelus, who was gone to Venice for the purpose of persuading the crusaders to attack Constantinople and release Isaac, who had been deposed, blinded, and imprisoned by his brother Alexis Angelus, who reigned as Alexis III. from the year 1195. The crusaders listened to the promises of young Alexis, who was chiefly supported by Baldwin of Flanders, as he is generally called; and they left Venice with a powerful fleet, commanded by the doge of Venice, Dandolo, who was also commander-in-chief of the whole expedition. The various incidents and the final result of this bold undertaking are given under ALEXIS III., IV., and V. The usurper Alexis III. was driven out by the crusaders ; prince Alexis and his father Isaac succeeded him on the throne; both perished by the usurper Alexis V. Ducas Murzuphlus; and Murzuphlus in his turn was driven out and put to death by the crusaders in 1204. During this remarkable war Baldwin distinguished himself by his military skill as well as by his personal character, and the crusaders having resolved to choose one of their own body emperor of the East, their choice fell upon Baldwin.

Baldwin was accordingly crowned emperer at Constantinople, on the 9th of May, 1204. But he received only avery small part of the empire, namely Constantinople and the greater part of Thrace; the Venetians obtained a much greater part, consisting chiefly of the islands and some parts of Epeirus ; Boniface, marquis of Monteferrato, received Thessalonica, that is Macedonia, as a kingdom; and the rest of the empire, in Asia as well as in Europe, was divided among the French, Flemish, and Venetian chiefs of the expedition. The speedy ruin of the new Latin empire in the East was not doubtful under such divisions; it was hastened by the successful enterprises of Alexis Comnenus at Trebizond, of Theodore Lascaris at Nicaea, and by the partial revolts of the Greek subjects of the conquerors. Calo-Ioannes, king of Bulgaria, supported the revolters, who succeeded in making themselves masters of Adrianople. Baldwin laid siege to this town; but he was attacked by Calo-Ioannes, entirely defeated on the 14th of April, 1205, and taken prisoner. He died in captivity about a year afterwards. Many fables have been invented with regard to the nature of his death: Nicetas (Urbs Capta, 16) says, that Calo-Ioannes ordered the limbs of his imperial prisoner to be cut off, and the mutilated body to be thrown into a field, where it remained three days before life left it. But from the accounts of the Latin writers, whose statements have been carefully examined by Gibbon and other eminent modern historians, we must conclude, that although Baldwin died in captivity, he was neither tortured nor put to death by his victor. The successor of Baldwin I. was his brother Henry I. (Nicetas, Alexis Isaacius Anyelus Fr. 3.9, Alexis Ducas Murzuphlus, 1.1, Urbs Capta, 1-17; Acropolita, 8, 12; Nicephorus Gregor. 2.3, &c.; Villehardouin, De la Conqueste de Constantinoble, ed. Paulin Paris, Paris, 1838.)