Helsinki was established as a trading town by King Gustav I of Sweden in 1550 as the town of Helsingfors, which he intended to be a rival to the Hanseatic city of Reval (today known as Tallinn). Little came of the plans as Helsinki remained a tiny town plagued by poverty, wars, and diseases. The plague of 1710 killed the greater part of the inhabitants of Helsinki. The construction of the naval fortress Sveaborg (In Finnish Viapori, today also Suomenlinna) in the 18th century helped improve Helsinki's status, but it was not until Russia defeated Sweden in the Finnish War and annexed Finland as the autonomous Grand Duchy of Finland in 1809 that the town began to develop into a substantial city. During the war, Russians besieged the Sveaborg fortress and most of the city was devastated in an 1808 fire.
Czar Alexander I of Russia moved the Finnish capital from Turku to Helsinki in 1812 to reduce Swedish influence in Finland and bring the capital closer to St. Petersburg. Following the Great Fire of Turku in 1827, The Royal Academy of Turku, back then the country's only university, was also relocated to Helsinki, and eventually became the modern University of Helsinki. The move consolidated the city's new role and helped set it on the path of continuous growth. This transformation is highly apparent in the downtown core, which was rebuilt in neoclassical style to resemble St. Petersburg, mostly to a plan by the German-born architect C. L. Engel. As elsewhere, technological advancements such as railroads and industrialization were key factors behind the city's growth.
Despite the tumultuousness of Finnish history during the first half of the 20th century, Helsinki continued its steady development. A landmark event was the XV Olympiad (1952 Olympic Games) held in Helsinki. Finland's rapid urbanization in the 1970s, occurring late relative to the rest of Europe, tripled the population in the metropolitan area, and the Helsinki Metro subway system was built
