Dumbarton Castle and Dumbarton Rock

Dumbarton Castle has the longest recorded history of any stronghold in Scotland. It sits on Dumbarton Rock, a volcanic plug of basalt formed between 330 and 340 million years ago in the Early Carboniferous, when the area around present-day Glasgow saw widespread volcanic activity; the softer exterior eroded away and left the harder core standing.

Archaeological finds show the rock was a strategically important settlement at least as far back as the Iron Age, and the people living there in the Roman period are known to have traded with the Romans. The first written record of a settlement is a letter St Patrick wrote to King Ceretic of Alt Clut in the late fifth century.

From the fifth century to the ninth the rock was the centre of the independent Brythonic kingdom of Strathclyde. Alt Clut — the Rock of the Clyde — was the Brythonic name for Dumbarton Rock and became a byword for the kingdom itself. The king of Dumbarton about AD 570 was Riderch Hael, who appears in Welsh and Latin works. Legend attached itself early. Merlin was said to have stayed at Alt Clut, and the medieval Scalacronica of Sir Thomas Grey records the story, first told by Geoffrey of Monmouth, that Arthur left his nephew Hoël of Brittany sick at Alcluit in Scotland, where he was besieged by the Scots and Picts before recovering.

The first recorded loss of the rock came in 756, when a joint force of Picts and Northumbrians took the fortress after a siege and lost it again a few days later. By 870 it held a tightly packed British settlement, both fortress and capital of Alt Clut. In 871 the Irish-based Viking kings Amlaíb Conung and Ímar besieged the rock. It fell in four months, after its water supply failed, and the kings returned to Ireland with 200 ships and a host of British, English and Pictish captives. Those prisoners may have included the ruling family of Alt Clut, among them King Arthgal ap Dyfnwal, killed the following year in uncertain circumstances.

In medieval Scotland Dumbarton — Dùn Breatainn, the fortress of the Britons — was an important royal castle. It is believed to be the place Sir John Menteith took William Wallace on the way to London after his capture.

Malcolm Fleming of Fulwood, governor in 1333 and formerly tutor to the young David II, sheltered the king and his wife Joan of the Tower after the Scottish defeat at Halidon Hill on 19 July, then conveyed them safely to France. He returned to Dumbarton and held it against an English siege, protecting the seventeen-year-old Robert the Steward, and David II made him the first Earl of Wigtown — the first new Scottish earldom in more than a century.

Wigtown was still governor in 1361 when the Black Death swept into Scotland again and a third of the castle's garrison died. In 1425 James the Fat, youngest son of Murdoch Stewart, Duke of Albany, marched on Dumbarton and burned the town but could not take the castle, which Sir John Colquhoun held against him. Mary, Queen of Scots stayed here in July 1563, and after her defeat at Langside in 1568 she tried to reach the castle but went to England instead. John Fleming, 5th Lord Fleming, its keeper, went into England with her and was allowed to return.

Fleming's defence of Dumbarton for Mary during the Marian Civil War was staunch, helped by supply ships arriving from France under his cousin Thomas Fleming. The first siege was lifted by the assassination of Regent Moray in January 1570, and the assassin, James Hamilton of Bothwellhaugh, was welcomed at the castle. Fleming's attempt to ambush the English general William Drury in May 1570 failed and was satirised in a ballad printed that month, The tressoun of Dumbertane.