Swedish naval commander responsible for the overwhelming Swedish victory at the Second Battle of Svensksund, one of the largest naval battles in history. He is often better remembered, however, as the commander of the fortress of Sveaborg during the Finnish war of 1808, which was fought between Sweden and Imperial Russia, and ended in Cronstedt surrendering the fortress.
After Finland became independent in 1917, Sveaborg became a Finnish garrison and was renamed in Finnish as Suomenlinna. It served as a prison camp after the Civil War in 1918-1919. Suomenlinna was in military use for the last time during the Second World War when it served as one of Helsinki's air surveillance centres. It served as a garrison until 1972. Its use for tourism and recreation began on a larger scale after 1963. Only the Naval Academy remains on Suomenlinna to this day.