The first siege of Dumbarton was lifted because of the assassination of Regent Moray in January 1570. The assassin James Hamilton of Bothwellhaugh  was welcomed at Dumbarton. Fleming's defence of Dumbarton for Mary was satirized in a ballad printed by Robert Lekprevik in May 1570; "The tressoun of Dumbertane." Attributed to Robert Sempill, the ballad describes Fleming's failed ambush of Sir William Drury in May 1570. In October 1570 during the Marian civil war the castle was fortified for Mary against the supporters of James VI of Scotland with stones obtained by demolishing churches and houses in Dumbarton and Cardross. The castle was captured by the forces of Regent Lennox led by Thomas Crawford of Jordanhill and John Cunningham of Drumquhassle in the early hours of 2 April 1571, who used ladders to scale the rock and surprise the garrison.