Andronikos II Palaiologos immediately showed support for his Genoese allies by arresting the Venetian survivors of the massacre, including the Venetian bailo Marco Bembo. Venice threatened war with the Byzantine Empire, demanding reparations for the affront they suffered. In July 1296, the Venetian fleet, under command of Ruggiero Morosini Malabranca, stormed the Bosphorus. During the course of the campaign, various Genoese possessions in the Mediterranean and the Black Sea were captured, including the city of Phocaea. The Genoese colony of Galata, across the Golden Horn from the Byzantine capital, was also burned down. The Byzantine basileus, however, preferred at that point to avoid war. Open war between Venice and the Byzantines did not begin until after the Battle of Curzola and the end of the war with Genoa in the 1299 Treaty of Milan, which left Venice free to pursue her war against the Greeks. War of 1350–1355 Disputes over Black Sea prompted the outbreak of another war in 1350, in which Venice allied with King Peter IV of Aragon, who was at odds with Genoa over control of Sardinia and the commercial rivalry between his Catalan subjects and the Genoese, and entered the war in 1351. Following clashes between local forces in the Aegean and around the Bosphorus, in 1351 a major Genoese fleet under Paganino Doria besieged the Venetian colony of Negroponte before advancing to Constantinople. The Byzantine Emperor John VI, who had lost a short war with the Genoese in 1348–1349, had been induced to enter the war on the Venetian side and assisted them in attacks on Pera. A combined Venetian-Catalan fleet under Niccolo Pisani and the Catalan Ponce de Santapau arrived soon afterwards and joined forces with the Byzantines, and the bloody battle of the Straits was fought in the Bosphorus in February 1352. Both sides suffered heavy casualties, but the most serious losses were inflicted on the Catalans, inducing Pisani to withdraw and enabling Doria to force Byzantium out of the war. In August 1353, Pisani led the Venetians and Catalans to a crushing victory over the Genoese under Antonio Grimaldi off Alghero in Sardinia. Alarmed by the defeat, Genoa submitted to Giovanni Visconti, Lord of Milan, in order to secure his financial support. In 1354 Paganino Doria caught Pisani unprepared in his anchorage at Zonklon (Sapienza) in the Peloponnese and captured the entire Venetian fleet. This defeat contributed to the deposition of doge