Frankish Greece refers to the period of Greek history following the Fourth Crusade in 1204, when the Latin Empire was established in Constantinople. During this time, various regions of Greece were ruled by Frankish lords and knights, leading to the creation of several feudal states, such as the Principality of Achaea and the Duchy of Athens. This era saw significant cultural and political changes, as Western European influences merged with local traditions. The Frankish rulers introduced new administrative systems and fortified castles, which shaped the landscape and society of Greece until the Ottoman Empire began its expansion in the 15th century.