BALDWIN I. (1172-1205), emperor of Rumania, count of Flanders and Hainaut, was one of the most prominent leaders of the fourth crusade. On the capture of Constantinople he was elected first emperor of Rumania (May 9, 1204) and crowned a week later, after the imperial crown had first been refused by Doge Dandolo. Besides being feudal superior of the princes in vested with portions of the conquered territory, Baldwin received as his own portion Constantinople, the adjacent regions both on the European and the Asiatic side, along with some outlying districts, and several islands, including Lemnos, Lesbos, Chios and Tenos. He at once marched into Thrace to conquer the allotted territory, with the intention of occupying Thessalonica. He was immedi ately involved in a conflict with Boniface of Montferrat, who had been his rival candidate for the empire, and had been invested, in compensation, with a large territory in Macedonia and the title of king of Salonika. Bonif ace aimed at complete independence of the empire, and civil war between the rivals was only averted by the mediation of Dandolo, who persuaded Baldwin to agree to the establishment of the kingdom of Salonika. In the following winter the Franks made conquests in Bithynia, in which Henry, Baldwin's brother, took part ; but in Feb. i 205 the Greeks revolted in Thrace, relying on the assistance of John (Kaloyan), tsar of Bulgaria, whose overtures of alliance had been unwisely rejected by the emperor. In a desperate battle under the walls of Adrian ople (April 15, 1205) the crusaders were defeated, the count of Blois slain and Baldwin captured. He was taken to the Bulgarian capital Trnovo, where a tower is still known as "Baldwin's tower," and held hostage; but he was afterwards killed by the Bulgarian tsar. The manner of his death is obscure. Kaloyan wrote to Pope Innocent III. that he had died in prison ; but one contemporary writer says that his hands and feet were cut off and he was thrown into a valley, where he died on the third day. His brother Henry, who had acted as regent since his capture, succeeded him as Emperor in 1206, when his death was definitely known.
See Ducange, Histoire de l'empire de Constantinople sous les empereurs francais (i657) ; G. Finlay, History of Greece, vol. iv. (1877) ; Pears, The Fall of Constantinople (i885) ; Gerland, Geschichte des lateinischen Kaiserreiches von Konstantinopel, pt. i. (Homburg v. d. Hobe, 1905) ; W. Miller, The Latins in the Levant (1908) ; Gibbon, Decline and Fall, vol. vi. (ed. Bury, 1912) . (J. B. B.)