Helsinki was founded in 1550 by King Gustav Vasa of Sweden as a trading post to compete with Tallinn to the south in Estonia, which was Danish at that time. In 1748 Sweden built the massive Suomenlinna Maritime Fortress off the coast of Helsinki to counter the growing threat from Russia. In 1809, Finland was annexed to Russia during a war of that period and the capital of Finland moved from Turku to Helsinki in 1812. A monumental city plan was drawn up in Empire style to reflect the power of Russia and the Tsar. This can be seen today, for example, around the Lutheran Cathedral, which was completed in 1852. By the early 20th century, the population of Helsinki exceeded 100,000, helped by its university and growing industry.