The Alcazaba of Antequera was erected in the 14th century to counter the Christian advance from the north, over Roman ruins.
The fortress is rectangular in shape, with two towers. Its keep (Torre del homenaje, 15th century) is considered amongst the largest of Moorish al-Andalus, with the exception of the Comares Tower of the Alhambra. It is surmounted by a Catholic bell tower/chapel (Templete del Papabellotas) added in 1582.
Connected to the former by a line of walls is the Torre Blanca ('white tower').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.