Tarifa Castle was built in 960 by the Abd-ar-Rahman III, Caliph of Córdoba. When Tarifa was taken over by the king of Castile, Sancho IV in 1292, the castle was handed over to Alonso Pérez de Guzmán for its defense. Pérez de Guzmán get the nickname of 'Good' (el Bueno) by refusing to hand over the castle in 1296 to the besieging forces of the Infante Don Juan, the rebellious brother of the king Sancho, and the Marinids, in exchange for the life of his son.
Due to the castle's irregular oblong shape, some believe it was built on the remains of a Roman fort. To the east, two high towers protect the castle - one is called Torre de Guzman El Bueno; the order for the Moors to kill Guzman's son was given from here. Outside the castle you can see a statue of the king who first reconquered the town from the Moors in 1292, Sancho IV. There's a statue of Guzman himself just over the road on the Alameda.
Recently refurbished, the castle is open to visitors. The coast and mountains of Morocco are visible from its towers.
References:Carlsten is a stone fortress built on the orders of King Carl X of Sweden following the Treaty of Roskilde, 1658 to protect the newly acquired province of Bohuslän from hostile attacks. 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 labour, until 1860 when it was reported finished. 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 Gyldenløve, 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.