During this period, Greece was being fought over by the Roman (Byzantine) Empire, Catholic crusader states, mercenary bands, Venice, and the Ottoman Empire. The Ottomans won. The Peloponnese (The peninsula Sparta and Corinth are on) was intially controlled by a Frankish Catholic principality called the Principality of Achea, which was gradually taken over and held by Roman Empire and its brief successor states until 1460, when the Ottomans took over. Athens was also controlled by various Catholic Dukes, the last of which was eventually ousted by the Ottomans in Islands in the Aegean and around the coast of the peninsula were held by Venice, until the Ottomans gradually took them over. Greece and the Balkans were seen as a battleground in the fight against the rising Ottoman Empire, leading the pope to declare a crusade in the 15 century to reclaim the land.