the last Latin emperor of Constantinople, who lost his throne in 1261 when Michael VIII Palaeologus restored Greek rule to the capital.

The son of Yolande, sister of Baldwin I, the first Latin emperor of Constantinople, and Peter of Courtenay, the third Latin emperor, he came to the throne after the death of his brother Robert, the fourth emperor, in 1228. In his minority the regency was entrusted to John of Brienne. During this time, invasions by the Greeks under the emperor John III Ducas Vatatzes at Nicaea and by the Bulgars (Bulgar) under Tsar John Asen II substantially reduced the territory of the empire, leaving only the area around Constantinople to the Latins. In 1236 and 1245 Baldwin went to western Europe to solicit funds and military aid; his treasury was empty, and he was forced to break up parts of the imperial palace for firewood. He sold a large number of alleged relics that had been kept at Constantinople, including Jesus' crown of thorns and a large portion of the True Cross, to the French king Louis IX, who placed them in the Sainte-Chapelle in Paris. When Michael VIII Palaeologus captured Constantinople on July 25, 1261, Baldwin fled through Greece to Italy and France. In May 1267 he persuaded Charles of Anjou (Charles I), king of Naples and Sicily, to pension him and sign a treaty for the reconquest of the empire; in October 1273 he married his son Philip to Charles's daughter Beatrice. Nothing came of this alliance, however, for Baldwin died a few days later.