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:
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.