Malahide Castle (Irish: Caisleán Mhullach Íde), parts of which date to the 12th century, lies, with over 260 acres (1.1 km2) of remaining estate parkland (the Malahide Demesne Regional Park), close to the village of Malahide, nine miles (14 km) north of Dublin in Ireland.
The estate began in 1185, when Richard Talbot, a knight who accompanied Henry II to Ireland in 1174, was granted the 'lands and harbour of Malahide'. The oldest parts of the castle date back to the 12th century and it was home to the Talbot family for 791 years, from 1185 until 1976, the only exception being the period from 1649–60, when Oliver Cromwell granted it to Miles Corbet after the Cromwellian conquest of Ireland; Corbet was hanged following the demise of Cromwell, and the castle was restored to the Talbots. The building was notably enlarged in the reign of Edward IV, and the towers added in 1765.
The estate survived such losses as the Battle of the Boyne, when fourteen members of the owner"s family sat down to breakfast in the Great Hall, and all were dead by evening, and the Penal Laws, even though the family remained Roman Catholic until 1774.
In the 1920s the private papers of James Boswell were discovered in the castle, and sold to American collector Ralph H. Isham by Boswell"s great-great-grandson Lord Talbot de Malahide.
Malahide Castle and Demesne was eventually inherited by the 7th Baron Talbot and on his death in 1973, passed to his sister, Rose. In 1975, Rose sold the castle to the Irish State, partly to fund inheritance taxes. Many of the contents, notably furnishings, of the castle had been sold in advance leading to considerable public controversy, but private and governmental parties were able to retrieve some. Rose Talbot, one of the last surviving members of the Talbot family died at Malahide House, Tasmania in 2009. Her closest relatives, who married into the German surname Dietsch, travelled to Canada and the United States of America. Members of the Dietsch family still live in the USA and Canada today.
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.