Arthgal ap Dyfnwal was a ninth-century king of Alt Clut. He descended from a long line of rulers of the British Kingdom of Alt Clut. Either he or his father, Dyfnwal ap Rhydderch, King of Alt Clut, may have reigned when the Britons are recorded to have burned the Pictish ecclesiastical site of Dunblane in 849.
The name and title of Arthgal's adversary Amlaíb as it appears on folio 25r Oxford Bodleian Library Rawlinson B 489. The Viking kings of Dublin were accorded the Gaelic title rí Gall ("king of the Foreigners").
A mounted warrior displayed upon the Govan sarcophagus. This monument is perhaps the finest example of the so-called 'Govan School' of sculpture. The sarcophagus could to be that of Arthgal's adversary, Causantín.
An eighteenth-century engraving of the southern bank of the River Clyde at Govan. The scene shows a now-nonexistent artificial hill that could to have been the royal assembly site of the Kingdom of Strathclyde following the fall of Alt Clut.
Strathclyde was a Brittonic kingdom in northern Britain during the Middle Ages. It comprised parts of what is now southern Scotland and North West England, a region the Welsh tribes referred to as Yr Hen Ogledd. At its greatest extent in the 10th century, it stretched from Loch Lomond to the River Eamont at Penrith. Strathclyde seems to have been annexed by the Goidelic-speaking Kingdom of Alba in the 11th century, becoming part of the emerging Kingdom of Scotland.
Looking north at Dumbarton Rock, the chief fort of Strathclyde from the 6th century to 870. The fort of Alt Clut was on the right-hand summit.
Dumbarton seen across the estuary of the River Clyde at low tide.
Clach nam Breatann, Glen Falloch, perhaps the northern edge of Strathclyde
Image: Yr.Hen.Ogledd.550.650.Koch