In Russia, Saint Petersburg is historically and culturally associated with the birth of the Russian Empire and Russia's entry into modern history as a European great power. The city was founded by Tsar Peter the Great on on the site of a captured Swedish fortress, and was named after apostle Saint Peter. As Russia's Imperial capital, and a historically strategic port, it is governed as a federal city. Saint Petersburg is the fourth-most populous city in Europe, the most populous city on the Baltic Sea, as well as the world's northernmost city with over 1 million residents. It is situated on the Neva River, at the head of the Gulf of Finland on the Baltic Sea, with a population of roughly 5.4 million residents. Sankt-Peterburg, IPA: ( listen)), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), is the second-largest city in Russia.