Clontarf Castle was burned in 1641 by the Governor of Dublin, Sir Charles Coote, apparently in revenge for the disloyalty of the then owner, George King. The castle, estate and district were given in 1649 by Oliver Cromwell to John Blackwell, who assigned his interest to John Vernon, Quartermaster-General of Cromwell's army in Ireland, although this is described in Lewis's Topographical Dictionary of 1837 as “conferred by the Crown on Admiral Vernon”. The Vernon family subsequently occupied the Castle for nearly three hundred and fifty years.