at the beginning of the fourteenth century, the consequences of the Byzantine reconquest of 1261 on the expansion of Latins into the Aegean and the Balkans were clearly felt. Michael VIII Palaeologus had opened access to the Black Sea to the Genoese by the Treaty of Nymphaeum, and to the Venetians in the years that followed, and recognised the principal conquests made by the latter after the Fourth Crusade. A chain of ports of call and trading-posts stretched along the main sea routes, since Andronikos II had abandoned the maintenance of a Byzantine fleet as too costly. The Aegean Sea was thus at the heart of the great trade routes which led from Italy to Constantinople and the Black Sea, Cyprus and Lesser Armenia, Syria and Alexandria. Control of the islands and coasts became a vital necessity for the Italian maritime republics and the object of frantic competition between them: from this sprang the three ‘colonial’ wars between Genoa and Venice in the course of the fourteenth century. Their only result was a de facto sharing of the Aegean: Venice had the western and southern coasts, with Messenia, Crete and Negroponte, Genoa the eastern coasts with Chios and Mytilene, while the Catalans were to come to disturb Italian maritime and commercial hegemony through their domination over the duchy of Athens and the rapid development of piracy.