Very little is known of the Kantara castle's early days. It is thought to have been built by the Byzantines, probably after the last of the Arab raids in the late 10th century. However there are no remains or records dating from that time. Its first mention was in 1191, during Richard the Lionheart's Crusade to the Holy land. It was at Kantara that the self-styled king, Isaac Commenos, sheltered before surrendering to the English King.
In the 13th century, the castle was remodelled by the Lusignans, and during the next few hundred years, the castle often served as a shelter for defeated barons and kings. When the Genoese conquered Famagusta and Nicosia in 1373, Kantara remained undefeated in the hands of the King. It was here too, that Prince John, the king's brother, fled, disguised as a cook, after his escape from the Genoese. The story goes that the prince, having been captured in Famagusta with the rest of the Royal Family, was imprisoned in irons. With the aid of his faithful servant and cook, he escaped, dressed as the cook's scullion, with an old cooking pot over his head, and carrying a frying pan which he was supposedly taking to be re-tinned. After the peace treaty with the Genoese, Kantara was further re-fortified. Most of the castle that we see today dates from around this time.
When the Venetians took over the island in 1489, the castle continued as an important garrison for the defence of the area. However, the art of warfare was changing, and the Venetians strengthened the fortifications at Kyrenia, Famagusta and Nicosia. The castle was abandoned in 1525, though there are records showing the castle as still fortified in 1529. However records show the castle in ruins by 1562.References:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.