Venice was a sovereign territory.
Republic of Venice . Serenissima Repubblica di Venezia ) , was a sovereign state and maritime republic in northeastern Italy , which existed for a millennium between the 8th century and the 18th century . Venice . The city was historically the capital of the Republic of Venice . After the Napoleonic Wars and the Congress of Vienna , the Republic was annexed by the Austrian Empire , until it became part of the Kingdom of Italy in 1866 , following a referendum held as a result of the Third Italian War of Independence .