Latin Empire of Constantinople

Also known as Imperium Constantinopolitanum, Latin Romania

The short-lived Frankish empire founded on the ruins of Byzantium after the sack of Constantinople in 1204, and the parent state of the broader Frankish Greece.

The Latin Empire was the Crusader state created by the leaders of the diverted Fourth Crusade after the sack of Constantinople on 12–13 April 1204. The crusade leadership and their Venetian allies divided the Byzantine territories under the Partitio Romaniae treaty: a fourth and an eighth went to the new emperor, three-eighths to the rest of the Crusader nobility, and three-eighths (almost all the strategic ports) to Venice. Baldwin IX of Flanders was elected the first Latin emperor on 9 May 1204 and crowned in Hagia Sophia.

From its capital at Constantinople the empire claimed sovereignty over almost all the former Byzantine lands, but its actual control was thin and uneven. A constellation of Frankish vassal states emerged within and beside it — the Kingdom of Thessalonica, the Principality of Achaea, the Duchy of Athens, the Aegean Duchy of Naxos — while Greek successor states at Nicaea, Trebizond, and Epirus carried on the imperial tradition in opposition. The empire was almost continuously at war on multiple fronts.

The empire was retaken by Michael VIII Palaiologos of Nicaea, who entered an undefended Constantinople on 25 July 1261 and restored the Byzantine Empire under his own dynasty. The titular Latin imperial line carried on in exile in Italy and France for another century; the daughter-states in Greece survived much longer, but the central Latin Empire itself lasted just fifty-seven years.

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