The British hero Arthur has been a headache for scholars. Some maintain that there is no historical evidence for him, and that he is as mythical as Robin Hood or Father Christmas. In what follows, we turn that upside down. Arthur is as historical as Oliver Cromwell or Abraham Lincoln, and we have plenty of hard information on him, including the place and date of his death: in 537 at Camlan or Castlesteads, on Hadrian's Wall, north- east of Carlisle. Like his other battles, it belongs to southern Scotland and the Borders. How we reach that solution is the purpose of this Chapter.

Authentic knowledge of Arthur comes from three sources: a polemical tract written by Gildas in 536 and mentioning the Battle of Mount Badon of 493; the entry for 537 in Annales Cambriae; and a list of 12 battles in the ninth- century Historia Brittonum, which includes Badon. We start with the second as edited by John Williams ab Ithel (1811– 1862). It reads, ‘Gueith Camlann, in qua Arthur et Medraut corruere; et mortalitas in Britannia et Hibernia fuit.’ The editor explained gueith as Old Welsh for ‘battle’, while Camlann was identified by the archaeologist O. G. S. Crawford (1886– 1957) as the fort of Camboglanna on Hadrian's Wall. The ‘Medraut’ who fell with Arthur is otherwise unknown. As for mortalitas, it has been translated as ‘plague’, but it should be taken as ‘famine’, part of a worldwide one during the volcanic winter of 536– 37, the consequence of a volcanic eruption in the Americas, probably at Ilopango in El Salvador. The reasoning for that appears below.

Now for Gildas. There are two references in his work. In the first, after telling how the Britons under Ambrosius Aurelianus resisted Anglo- Saxon aggression, he states in Chapter 26 that the struggle went this way and that ‘up to the year of the siege of Badon Hill (obsessionis Badonis montis)’, which was ‘also the year of my birth’ 43 years and a month prior to the time of writing. The second reference is in Chapter 93, where he alludes to ‘a certain thick mist and black night’ sitting ‘upon the whole island’ of Britain. In 2010 it was referred by Dr David Woods to the cloud of volcanic ash covering the Northern Hemisphere in 536– 37.