One of the leaders of the Fourth Crusade (1202-1204) and subsequently first Latin emperor of Constantinople (1204-1206).
Baldwin was born in July 1171, the son of Baldwin V, count of Hainaut, and Margaret, countess of Flanders. He married Mary, sister of Count Thibaud III of Champagne, by whom he had two daughters, Jeanne and Margaret. In 1192 he succeeded to Flanders and Hainaut (he is usually numbered as Baldwin IX and VI in this context). He gave proof of his ability as a politician by changing the direction of the foreign policy of Flanders: by allying himself with King Richard I of England he succeeded in resisting the encroachments of Philip II Augustus of France, whom he defeated in a series of battles, and then negotiated the Treaty of Péronne, in which he recovered much of the territory annexed by Philip some years earlier.
Baldwin took the cross on 23 February 1200 together with his wife, Mary; his brother, Henry; and many knights. He was represented at Venice in the negotiations concerning the transport of the crusade army by Conon of Béthune and Alard Maquereau. In 1201 he organized a fleet under the command of John of Nesle and left Flanders (on 14 April, Easter) by the land route. He was one of the first crusaders to reach Venice (probably in July) and was also one of those who contributed plate and money to try to meet the debt to the Venetians before the fleet could sail. Baldwin is not mentioned in connection with the attack on Zara (mod. Zadar, Croatia), but at Corfu (mod. Kerkira, Greece) he joined with the other leaders in trying to convince the army to accept the offer of the exiled Byzantine prince Alexios Angelos.
When the crusade arrived at Constantinople (mod. Istanbul, Turkey), Baldwin was put in command of the vanguard, according to the chronicler Geoffrey of Villehardouin, because of the number of archers and crossbowmen in his troop. He led the vanguard in the abortive encounter with Alexios III Angelos and his army outside the gates of Constantinople; when his troops halted their advance at the sight of the much larger Greek army, he was accused of cowardice by the squadron of Hugh, count of Saint-Pol, and was told by his own men that they would no longer acknowledge him unless the advance continued. The Greeks withdrew while the crusaders were still in some confusion, but the incident shows that Baldwin had difficulty controlling his troops. Baldwin does not seem to have had a prominent role during the reign of the co-emperors Isaac II and Alexius IV, but he was among those who negotiated the agreement with the Venetians on how to divide the empire once the crusaders had decided to attack Constantinople a second time.
Baldwin quickly emerged as the leading rival to Boniface of Montferrat in the election for a new emperor; on 9 May 1204 he was elected as Latin emperor, largely because the Venetians had no intention of allowing any increase in the power of their Italian neighbor Boniface. Eight days later Baldwin was crowned in the Church of St. Sophia in a ceremony that included as much of the traditional Byzantine pomp and ceremony as possible, which made him the rightful emperor in the eyes of many Greeks. He reluctantly agreed to the request of Boniface that he should have Thessalonica (mod. Thessaloniki, Greece) and its environs instead of Asia Minor. Baldwin then set out to campaign against Alexios V Doukas Mourtzouphlos and marched to Adrianople (mod. Edirne, Turkey), where his brother, Henry, had preceded him. As Baldwin advanced on to Mosynopolis, his advisers made trouble between him and Boniface by advising that he should insist on his right to go to Thessalonica, despite Boniface’s request that he should not. On arriving in Thessalonica, Baldwin acted as overlord, renewing the privileges of the Greeks while a furious Boniface campaigned in Thrace for the recognition of his stepson Manuel (the son of Isaac II and Margaret of Hungary) as the rightful emperor. Open warfare was only avoided by the intervention of the other leaders of the crusaders and the tact of Geoffrey of Villehardouin.
With peace restored, Baldwin gave some attention at the beginning of 1205 to the administration of Flanders, while many of the knights departed to try to conquer the fiefs that had been granted to them in Thrace and across the straits in Asia Minor. At this point there was an influx of Franks from Palestine who came to join the crusaders, bringing the news that Baldwin’s wife, Mary, had died (9 August 1204), which distressed him greatly. In March 1205 the Greeks in Thrace rebelled, supported by an invasion by Kalojan, the ruler of Bulgaria, whose overtures the crusading leaders had unwisely rejected. Baldwin summoned his men back to Constantinople, but the crisis in Thrace seemed so serious that he did not wait for the return of all of them and set off with whatever reinforcements he could muster. He besieged Adrianople with an inadequate number of men, and even the arrival of the doge of Venice with reinforcements added only a few to the army. Kalojan meanwhile was hastening to attack the besiegers, and the Cumans, his nomadic cavalry, lured the Franks into a disorderly attack in which they suffered severely and from which they had great difficulty extricating themselves (13 April). After the battle Baldwin held a council at which new battle orders were agreed on. No one was to leave the ranks to charge, but the knights were to keep their formation. Battle was resumed the next day (14 April), but the orders were ignored by Louis of Blois, who charged the Cumans, calling on Baldwin to follow him. Louis was fatally wounded, and Baldwin, who refused to escape, as it would be dishonorable, was captured and badly wounded. There was no definite news of him thereafter, but by 1206 the Franks were sufficiently certain that he was dead in captivity to crown his brother, Henry, as the new emperor. Rumors about Baldwin continued to circulate; in the 1220s an impostor had considerable success in Flanders, which had been misgoverned by Baldwin’s daughter Jeanne, and where his reign was remembered with affection. The impostor was exposed and executed by Jeanne.
Baldwin is depicted in contemporary sources as a brave and honorable man, but his behavior in Greece lacked the skill and finesse that he had shown when confronting Philip Augustus in the 1190s. He had exemplary piety and morality; the Greek chronicler Niketas Choniates commented admiringly on his fidelity to Mary even when they were separated. Yet he lacked any tact or flexibility when negotiating with the Greeks. His rigid insistence on his rights as overlord in his dealings with Boniface of Montferrat almost brought about a civil war among the crusaders, although Villehardouin, who certainly knew more than he said, put all the blame on Baldwin’s advisers. Baldwin’s position as emperor was fatally weakened by the presence of fellow crusaders like Louis of Blois and Boniface, who in the West had been his equals in rank and were reluctant to accept his orders. The power of the Venetians also hindered his freedom to maneuver. He showed little of the military and political skill of his successor, Henry, and during his brief reign the new Latin Empire was almost constantly under very serious threat of extinction.