   the duchy of athens was one of the crusader states set up in greece after the conquest of the byzantine empire during the fourth crusade, encompassing the regions of attica and boeotia, and surviving until its conquest by the ottoman empire in the 15th century. ==history== ===establishment of the duchy=== the first duke of athens (as well as of thebes, at first) was otto de la roche, a minor burgundian knight of the fourth crusade. although he was known as the "duke of athens" from the foundation of the duchy in 1205, the title did not become official until 1260. instead, otto proclaimed himself "lord of athens" (in latin dominus athenarum, in french sire d'athenes). the local greeks called the dukes "megas kyris" (, "great lord"), from which the shortened form "megaskyr", often used even by the franks to refer to the duke of athens, is derived. athens was originally a vassal state of the kingdom of thessalonica, but after thessalonica was captured in 1224 by [[
Byzantine_Empire_successor_states_in_the_Balkans Crown_of_Aragon Crusader_states Duchy_of_Athens Former_countries_in_the_Balkans Former_duchies Kingdom_of_Sicily Medieval_Athens Medieval_Boeotia States_and_territories_established_in_1205