Causantín mac Cináeda was King of the Picts from 862 until his death in 877. He is often known as Constantine I in reference to his place in modern lists of Scottish monarchs, but contemporary sources
A signboard in Fife, Scotland concerning Causantín
"Constantine's Cave" – also known as the Nigra Specus ("Black Cave") – at Balcomie near Crail in Fife, Scotland: the supposed death place of Causantín
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, ma
The fortress of Alt Clut occupied Alt Clut ("the rock of the Clyde"). The mediaeval citadel that sat atop this geological formation formed the capital of the Kingdom of Alt Clut before it was captured and destroyed by Amlaíb and Ímar.
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.