Also known as Alt Clyut or Altclut or variants thereof, being the Old Welsh for Clyde Rock; (in the modern Welsh Allt Clud) being the name under which Dumbarton was known throughout the early medieval period.

The citadel and capital of the kingdom of Strathclyde which was constructed on top of a plug of volcanic rock situated on the northern bank of the estuary of the river Clyde some fourteen miles west of Glasgow. Nowadays, nothing of this early medieval structure can be seen, (although archaeological excavations have confirmed its existence) obscured as it is by the later building known as Dumbarton Castle.

However the name Dumbarton itself, derived from the Goedelic Dun Breattann or "fortress of the British" serves as a reminder of its history as the capital of the almost forgotten Brythonic kingdom of Strathclyde.

Log in or register to write something here or to contact authors.