The loss of the British power base led to the emergence of the new kingdom of Strathclyde, or Cumbria, with a major centre at Govan.
The title "king of the Britons of Srath Clúade" was first used in 872.
The town is also served by eight primary schools; Aitkenbar Primary, St. From the mid 18th century to the early 19th century Dumbarton's main industry was glassmaking.
Michael's Primary, Knoxland Primary, Braehead Primary, St. As the glass industry declined the town became a major centre for shipbuilding and remained so well into the 20th century.
The castle was a royal fortress long before Dumbarton became a Royal Burgh; its ownership went from Scottish to English and back again.
The castle was an important place during the Wars of Independence and was used to imprison William Wallace for a short time after his capture by the English.
It was estimated that the flood defences would cost 30,000 pounds Scots, the cost being levied nationwide.However these industries have since declined, and Dumbarton today is increasingly a commuter town for Glasgow 13 miles (21 km) east-southeast of it. The bridge, with five segmental arches with rounded cutwaters, resulted in the extension of Dumbarton to West Bridgend. The fortress of Dumbarton was the stronghold of the kingdom of Alclud, and the centre of British power in northern Britain, for more than two centuries from the mid-seventh century, until the Vikings destroyed the fortress after a four-month siege in 870. Upon their marriage on , Prince Harry & Meghan Markle became the Earl & Countess of Dumbarton.In an attempt to lure the German aircraft away from the shipyards, decoy lights were routinely placed on the Kilpatrick hills above the town, lights were set out on reservoirs to mimic those of the shipyards reflecting on the waters of the Leven and Clyde.The ploy was sometimes successful in diverting the bombers and many bombs fell harmlessly onto the moors and lochs.