The Republic of Venice had once been the most powerful state in the Mediterranean. Almost impregnable because of the mashes that surrounded the city, Venice used its naval power to project military power abroad. In 1204 the Venetians diverted the Fourth Crusade to Constantinople fatally weakening the Byzantine Empire. As the Empire crumbled in coming years before the Ottoman onslaught Venice often stepped into the breach. Crete and many of the Greek Islands became Venetian. When the Lusignan dynasty died out in the 15th century Cyprus was annexed to Venice.
However, Venice itself now faced Ottoman pressure and economic decline from the opening up of alternative trade routes to Asia from the Atlantic. Cyprus was lost in 1571. Crete was lost in 1669 after a heroic 24 year siege. At the end of the century, Venice had one last gasp of glory conquering the Morea in Greece in 1699 (a campaign which severely damaged the Parthenon in Athens). The victory was fleeting. In 1718 at the end of the last Turkish-Venetian War, the Morea was lost and the Venetian Empire was restricted to Dalmatia and parts of Albania.
This commenced a long period of peace and decline of Venetian power. By 1792 the once mighty Venetian merchant fleet consisted of only 392 merchantmen. By 1796 the Venetian navy consisted of only 4 galleys and 7 galliots. The end came in 1797. Napoleon’s Italian campaign shattered the First Coalition against France. With Austria about to lose the Austrian Netherlands (Belgium) and Lombardy it was compensated at the expense of neutral Venice whose possessions were to be partitioned between France and Austria. Venice faced a French ultimatum and had no means to resist.
On May 12, 1797 Doge Ludovico Manin surrendered unconditionally and the Major Council of Venice declared an end to the Republic. The Republic had lasted 1100 years.
French troops occupied the city on May 16. In October Venice was handed over to Austria who would control it (apart from a period of French control between 1805-1815 under the Napoleonic Kingdom of Italy) until 1866 when it was returned to the new unified Kingdom of Italy.