Dumbarton has the longest recorded history of any castle in Scotland, and back in the era we are talking about, it was actually controlled by the Welsh. Dumbarton actually means “Fortress of the Britons” in Gaelic. Dumbarton Rock, on which the fortress is built, is an in-filled crater of a volcano that was active 350 million years ago.
The first mention of Dumbarton is by St. Patrick, whom you may recall was a native Briton, who mentions it in a letter written in the 5th century. It was also named by Nennius, whom we discussed in our video about King Arthur, as one of the 28 cities of sub-Roman Britain. According to legend, both Merlin and Arthur visited, and Geoffrey of Monmouth (who we also mentioned in the context of the Arthurian legend) writes that the castle was besieged by Scots and Picts.
The besieging is certainly accurate, and is why we’re talking about it today in the context of the Danes/Vikings. While the Saxons decried the Viking raid on Lindisfarne in 793, Saxon Northumbrians besieged the Welsh forces at Dumbarton in 756, capturing it only to lose it back to the Welsh a few days later. By 870, Dumbarton was the prosperous seat of the Welsh kingdom of Alt Clut. However, it fell in 871 to a Danish army from Dublin led by two brothers, Olaf and Ivar, after a four month siege. The pair returned to Dublin in 871 with 200 ships and “brought with them … a great prey” of Britons as slaves.
The Danes officially converted to Christianity in 965, though that didn’t stop their raiding or slave-taking in the slightest, at least for Danish controlled Dublin, for the first century afterwards.
Alexander II of Scotland built Dumbarton’s medieval castle in the 1220s as a defense against other Vikings, these from Norway, who still controlled portions of western Scotland. By then, the Danes themselves had been defeated in Ireland and, in other places, either driven out or converted to Christianity, at which point they adapted to their new country so much that they were now called something else.
This was particularly true in the case of the Danes who’d invaded France. As we talked about last season, those Danes eventually converted to Christianity and become Normans. What did not change, however, was their desire for conquest. And it’s the Norman religion, and their takeover of England, we’ll be talking about next week.