thumb|A 19th century tomb marker of the probable location of the tomb of Enrico Dandolo, the leader of the Fourth Crusade and Doge of Venice, inside the Hagia Sophia After the Sack of Constantinople, the crusaders agreed to divide up Byzantine territory. In the , signed on 1 October 1204, three eighths of the empire—including Crete and other islands—went to the Republic of Venice. The Latin Empire claimed the remainder and exerted control over: areas of Greece, divided into vassal fiefs: the Kingdom of Thessalonica the Principality of Achaea the Duchy of Athens the Duchy of the Archipelago the short-lived Duchy of Philippopolis in north Thrace Further duchies were projected in Asia Minor, at Nicaea (for Louis of Blois), Nicomedia (Thierry de Loos), Philadelphia (Stephen du Perche), and Neokastra. These duchies remained theoretical, due to the establishment of the Empire of Nicaea in the area. Nicaea itself was never occupied and Louis of Blois was killed in 1205. Thierry de Loos was captured by the Nicaeans in 1207 and, although released, left the Latin Empire two years later. After a brief Nicaean reconquest, Nicomedia returned to Latin control, but the remained part of the Imperial domain. Philadelphia never came under actual Latin control, although the Latin emperor Henry of Flanders laid claim to the region after defeating the local strongman, Theodore Mangaphas, in 1205. The duchy of Neokastra (ducatus Novi Castri) on the other hand was never accorded to a single holder, but was divided among the Knights Hospitaller (one quarter) and other feudatories. The term "duchy" in this case reflects the earlier Byzantine term theme, usually governed by a doux, to designate a province.
thumb|A 19th century tomb marker of the probable location of the tomb of Enrico Dandolo, the leader of the Fourth Crusade and Doge of Venice, inside the Hagia Sophia After the Sack of Constantinople, the crusaders agreed to divide up Byzantine territory. In the , signed on 1 October 1204, three eighths of the empire—including Crete and other islands—went to the Republic of Venice. The Latin Empire claimed the remainder and exerted control over: areas of Greece, divided into vassal fiefs: the Kingdom of Thessalonica the Principality of Achaea the Duchy of Athens the Duchy of the Archipelago the short-lived Duchy of Philippopolis in north Thrace Further duchies were projected in Asia Minor, at Nicaea (for Louis of Blois), Nicomedia (Thierry de Loos), Philadelphia (Stephen du Perche), and Neokastra. These duchies remained theoretical, due to the establishment of the Empire of Nicaea in the area. Nicaea itself was never occupied and Louis of Blois was killed in 1205. Thierry de Loos was captured by the Nicaeans in 1207 and, although released, left the Latin Empire two years later. After a brief Nicaean reconquest, Nicomedia returned to Latin control, but the remained part of the Imperial domain Philadelphia never came under actual Latin control, although the Latin emperor Henry of Flanders laid claim to the region after defeating the local strongman, Theodore Mangaphas, in 1205. The duchy of Neokastra (ducatus Novi Castri) on the other hand was never accorded to a single holder, but was divided among the Knights Hospitaller (one quarter) and other feudatories. The term "duchy" in this case reflects the earlier Byzantine term theme, usually governed by a doux, to designate a province.