In 1650, during the Third English Civil War, Oliver Cromwell’s Parliamentarian forces invaded Scotland, taking control of the south of the country after their victory at Dunbar in September. In February 1651, Cromwell found his lines of communication under attack from a small group of Royalists based at Tantallon Castle. This group, led by Alexander Seton, comprised just 91 men. Despite this, Cromwell sent 2,000 to 3,000 troops under General Monck, together with much of the artillery he had in Scotland, to lay siege to Tantallon. After twelve days of bombardment with cannon, a breach was made in the Douglas Tower. The defenders were compelled to surrender, but only after quarter had been granted to them in recognition of their bravery. After the siege, Tantallon was left in ruins. It was never repaired or inhabited afterwards.