Helsinki has experienced strong growth since the 1810s, when it replaced Turku as the capital of the Grand Duchy of Finland, which later became the sovereign Republic of Finland. The city continued its growth from that time on, with an exception during the Finnish Civil War. From the end of World War II up until the 1970s there was a massive exodus of people from the countryside to the cities of Finland, in particular Helsinki. Between 1944 and 1969 the population of the city nearly doubled from 275,000 to 525,600.