"Carlsten"@en . . . . . . . . "The site of Marstrand was chosen because of its location and its access to an ice free port. Initially a square stone tower was constructed, but by 1680 it was reconstructed and replaced by a round shaped tower. Successive additions to the fortress were carried out, by the inmates sentenced to hard labor, until 1860 when it was reported finished. Carlsten was exclusively a prison form men: Metta Fock was in 1806-1809 the only female prisoner to have been kept here. The fortress was decommissioned as a permanent defense installation in 1882, but remained in military use until the early 1990s."@en . . "The site of Marstrand was chosen because of its location and its access to an ice free port. Initially a square stone tower was constructed, but by 1680 it was reconstructed and replaced by a round shaped tower. Successive additions to the fortress were carried out, by the inmates sentenced to hard labor, until 1860 when it was reported finished. Carlsten was exclusively a prison form men: Metta Fock was in 1806-1809 the only female prisoner to have been kept here. The fortress was decommissioned as a permanent defense installation in 1882, but remained in military use until the early 1990s. The fortress was attacked and sieged twice falling into enemy hands. In 1677 it was conquered by Ulrik Frederick Gyldenl\u00F8ve, the Danish military commander in Norway and in 1719 by the Norwegian Vice-Admiral Tordenskjold. At both occasions the fortress was returned to Swedish control through negotiations and treaties."@en . .