The Empire of Romania (Latin: Imperium Romaniae), more commonly known in historiography as the Latin Empire (Greek: Λατινική Αυτοκρατορία) or Latin Empire of Constantinople, was a feudal Crusader state founded by the leaders of the Fourth Crusade on lands captured from the Byzantine Empire. It was established after the capture of Constantinople in 1204 and lasted until 1261. The Latin Empire was intended to supplant the Byzantine Roman Empire as titular successor to the Roman Empire in the east, with a Western Roman Catholic emperor enthroned in place of the Eastern Orthodox Roman emperors. Baldwin IX, Count of Flanders, was crowned the first Latin emperor as Baldwin I on 16 May 1204. The Latin Empire failed to attain political or economic dominance over the other Latin powers that had been established in former Byzantine territories in the wake of the Fourth Crusade, especially Venice, and after a short initial period of military successes it went into a steady decline. Weakened by constant warfare with the Bulgarians and the unconquered sections of the empire, it eventually fell when Byzantines recaptured Constantinople under Emperor Michael VIII Palaiologos in 1261. The last Latin emperor, Baldwin II, went into exile, but the imperial title survived, with several pretenders to it, until the 14th century.
The Latin Emperor was the ruler of the Latin Empire, the historiographical convention for the Crusader realm, established in Constantinople after the Fourth Crusade (1204) and lasting until the city was recovered by the Byzantine Greeks in 1261. Its name derives from its Catholic and Western European ("Latin") nature. The empire, whose official name was Imperium Romaniae (Latin: "Empire of Romania"), claimed the direct heritage of the Eastern Roman Empire, which had most of its lands taken and partitioned by the crusaders. This claim however was disputed by the Byzantine Greek successor states, the Empire of Nicaea, the Empire of Trebizond and the Despotate of Epirus. Out of these three, the Nicaeans succeeded in displacing the Latin emperors in 1261 and restored the Byzantine Empire.