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.References:
Angelokastro is a Byzantine castle on the island of Corfu. It is located at the top of the highest peak of the island"s shoreline in the northwest coast near Palaiokastritsa and built on particularly precipitous and rocky terrain. It stands 305 m on a steep cliff above the sea and surveys the City of Corfu and the mountains of mainland Greece to the southeast and a wide area of Corfu toward the northeast and northwest.
Angelokastro is one of the most important fortified complexes of Corfu. It was an acropolis which surveyed the region all the way to the southern Adriatic and presented a formidable strategic vantage point to the occupant of the castle.
Angelokastro formed a defensive triangle with the castles of Gardiki and Kassiopi, which covered Corfu"s defences to the south, northwest and northeast.
The castle never fell, despite frequent sieges and attempts at conquering it through the centuries, and played a decisive role in defending the island against pirate incursions and during three sieges of Corfu by the Ottomans, significantly contributing to their defeat.
During invasions it helped shelter the local peasant population. The villagers also fought against the invaders playing an active role in the defence of the castle.
The exact period of the building of the castle is not known, but it has often been attributed to the reigns of Michael I Komnenos and his son Michael II Komnenos. The first documentary evidence for the fortress dates to 1272, when Giordano di San Felice took possession of it for Charles of Anjou, who had seized Corfu from Manfred, King of Sicily in 1267.
From 1387 to the end of the 16th century, Angelokastro was the official capital of Corfu and the seat of the Provveditore Generale del Levante, governor of the Ionian islands and commander of the Venetian fleet, which was stationed in Corfu.
The governor of the castle (the castellan) was normally appointed by the City council of Corfu and was chosen amongst the noblemen of the island.
Angelokastro is considered one of the most imposing architectural remains in the Ionian Islands.