The site of this ancient seat of the Dukes of Hamilton was a fortress even in Viking times. The 13th century fortified tower was developed in the 16th century and extended by Cromwell in the 17th century. The foundation stone for the main Victorian extension was laid in 1844 by Princess Marie of Baden, wife of the 11th Duke of Hamiltion. Her granddaughter, Lady Mary Louise, 6th Duchess of Montrose, lived in the castle until 1957.