According to the Gazetteer of Scotland by Robert & William Chambers, Edinburgh, 1844 p268 (the entry for Dysart):
The most remarkable object of antiquity near the town is the castle of Ravenscraig, situated on a rock, projecting into the sea, at the east end of Kirkcaldy. It, with the lands adjoining, was given by James III. to William St. Clair, Earl of Orkney, when he resigned the title of Orkney. It has ever since been possessed by the family of St. Clair. It was inhabited in Oliver Cromwell's time, and was fired upon by a party of his troops. It has, for many years, been uninhabited and in a ruinous state.You can read the history of Ravenscraig Castle here.
William Sinclair (1410-1484), 3rd Earl of Orkney was my 12th Great Grandfather (i.e. great great great great great great great great great great great great grandfather). He was the Sinclair who built Rosslyn Chapel. Sadly, my branch of the family is descended from one of his many children from his three marriages and was disinherited in 1606 after a family dispute. Following this they were banished to Shetland where future generations lived quite poor lives. So there is not much change of me getting my castle back.
The area of St Clair in Kirkcaldy is also known as Sinclairtown or Sinclairton and includes street names like Rosslyn Street, Caithness Place and Sutherland Place which all relate to places important to the Sinclair family of that time. Click here for a map.