Under Alexander Robertson, 12th chief, the clan are said to have supported James Graham, 1st Marquess of Montrose in all of his battles during the Scottish Civil War. During this time, the main Robertson castle at Invervack, near the present Clan museum, was burned by Cromwell's forces, and many family records were lost. The Clan Robertson played a major part in the fighting at the Battle of Inverlochy (1645) in support of the royalist, James Graham, 1st Marquis of Montrose, where they put the king's enemies to flight. Alexander Robertson of Lude fought for Charles I of Scotland at the Battle of Tippermuir and as a result Lude was burned by Cromwell's forces in retaliation.