Description:The history of Dumbarton Castle stretches back 1,500 years, to when it was known as Alt Clut, "Rock of the Clyde". Over the centuries Dumbarton Rock has served as the centre of the British kingdom of Strathclyde, a medieval frontier post and an occasional royal residence. In the wake of the 1715 Jacobite Rising the castle became a garrison fortress, its impressive defences bristling with guns.