The Castle passed through many noble families until, passing by marriage in 1766, came to the hands of the 2nd Marquess of Bute. After turning Cardiff into the world’s greatest coal exporting port for it’s time he left the Cardiff Castle to his son, the 3rd Marquess of Bute who, in 1860, was reputed to be the richest man in the world. He also transformed the building that was given to him, into the majestic Castle we all know, beginning its transformation in 1865. It was back then when the 18 year old Marquess of Bute met the Gothic Revival architect William Burges. In the next 16 years their combined genius and the work of the finest craftsmen in Wels created the remarkable building that still exists. Beginning with the restoration of the South Gate and continuing with the Clock Tower and many of the rooms in the building, Burges left his mark on the entire castle.
Even after the death of William Burges in 1881 the work continued because of his detailed drawings of everything from exterior to interior and the help of his former assistant William Frame. Frame was responsible for the Animal Wall and for the restoring of the newly discovered Roman remains. After it was finished, the castle was used for about six weeks a year, when the Marquess would spend time in Cardiff. After the 3rd Marquess died in 1900 he left the estate to his son, John, who went on to complete a number of his father’s restoration projects.
During the Second World War the Castle largely escaped enemy action, although two adjacent lodges were destroyed, and the outer walls were used as air-raid shelters, capable of holding nearly 2000 people.
In 1947 the Castle was given to the people of Cardiff by the 4th Marquess of Bute, naming him to be the ‘man who sold a city’ after he sold out the remaining Bute family estate in Cardiff.