Which city was the capital of Finland before Helsinki became the capital?

Turku is Finland's oldest city and the first capital of Finland. It is not known when Turku was granted city status. Pope Gregory IX first mentioned the town of Aboa in his Bulla in 1229, and this year is now used as the founding year of the city. Turku was the most important city in the eastern part of the Kingdom of Sweden (today's Finland). After the Finnish War 1808-1809, Finland became an autonomous Grand Duchy of the Russian Empire in 1809, and Turku became the capital of the Grand Duchy. However, Turku lost its status as capital only three years later in 1812, when Czar Alexander I of Russia decided to move the capital to Helsinki. It was only after the last great fire in 1827 that most government institutions were moved to Helsinki along with the Royal Academy of Turku, founded in 1640, which later became the University of Helsinki, thus consolidating Helsinki's position as the new capital. Turku was Finland's most populous city until the late 1840s, and remains an important business and cultural centre, and a port.

Turku lies at the southwestern corner in the estuary of River Aura. The name means "marketplace" in Finnish. Turku has a well-preserved Medieval castle and Finland's largest cathedral. The population of Turku is approximately 202,000, while the metropolitan area has a population of approximately 311,000. It is the 6th most populous municipality in Finland, and the third most populous urban area in the country after Helsinki and Tampere.