The Castle of Zahara de los Atunes and Palace of Jadraza is a medieval castle on Spain's coast. In 1294, King Sancho IV of Castile granted a licence to Don Alonso Pérez de Guzmán to build traps for tuna fishing in reward for his heroic defense of Tarifa. Guzman fisheries in Zahara de los Atunes and Conil de la Frontera were for centuries the most productive in Europe provoking the development of important auxiliary buildings.
The Palace served three functions: as a fortified castle to protect against Barbary pirates, a residential palace during the Tuna Season and a processing plant to deal with the tuna. Its location at a strategic point of the Strait of Gibraltar has been given prominence in numerous historical events, and it maintains a continued presence in coastal mapping. In the twentieth century the building was used by the fishing industry before becoming a barracks.
Building is a square structure defined by four defensive walls with parapet surmounted with a narrow walkway. In the north-west corner is the so-called Torre de Poniente which has an inner chamber beneath a high domed roof also with a parapet. In the north-east are the remains of de la Torre de Levante. Both towers were designed as corbelled spaces to overlook the defensive curtain walls.
The main gateway is located in the west wall, the two sea gates are in the south, which originally also provided access to large patio inner enclosure of the building. In the twentieth century 'New Gate' was added in the north wall, where there are also various other piercings introduced for practical reasons as the use of the building developed over time.
The factory is made of regular masonry blocks with lime grout and pebbles. The corners boast reinforced stonework. The three original stone doors were of generous proportions with arches and keystones . At the sea gates, two separate buttresses of considerable thickness are arranged inward to reinforce them in their defensive mission.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.