Claim: Venice was a sovereign territory.

The Republic of Venice -LRB- Repùblica Vèneta Repubblica di Venezia -RRB- , traditionally known as the Most Serene Republic of Venice -LRB- Serenìsima Repùblica Vèneta  Serenissima Repubblica di Venezia -RRB- , was a sovereign state and maritime republic in northeastern Italy , which existed for a millennium between the 8th century and the 18th century . It was based in the lagoon communities of the historically prosperous city of Venice , and was a leading European economic and trading power during the Middle Ages and the Renaissance .   The Venetian city state was founded as a safe haven for the people escaping persecution in mainland Europe after the decline of the Roman Empire . In its early years , it prospered on the salt trade . In subsequent centuries , the city state established a thalassocracy . It dominated trade on the Mediterranean Sea , including commerce between Europe and North Africa , as well as Asia . The Venetian navy was used in the Crusades . Venice achieved territorial conquests along the Adriatic Sea . The city became home to an extremely wealthy merchant class , who patronized renowned art and architecture along the city 's lagoons . Venetian merchants were influential financiers in Europe . The city was also the birthplace of great European explorers , especially Marco Polo , as well as the classical music composer Vivaldi .   The republic was ruled by the Doge , who was elected by members of the Great Council of Venice , the city-state 's parliament . The ruling class was an oligarchy of merchants and aristocrats . Venice and other Italian maritime republics played a key role in fostering capitalism . Venetian citizens generally supported the system of governance . The city-state enforced strict laws and employed ruthless tactics in its prisons .   The opening of new trade routes to the Americas and the East Indies via the Atlantic Ocean marked the beginning of Venice 's decline as a powerful maritime republic . The city state suffered defeats from the navy of the Ottoman Empire . In 1797 , the republic was plundered by retreating Austrian and then French forces , following an invasion by Napoleon Bonaparte . Venice then became a part of a unified Italy in the 19th century .