Climate and plague

At the page “The first Mercian Lands” I have argued that a plausible historical context for the establishment of Mercia was the northward expansion of Wessex during the third quartile of the sixth century. This followed, if the general thrust of the various annals and chronicles is taken as reliable for this period, a period of relatively calm between the various ethnic groups in southern England – the peace following the Battle of Mons Badonicus as recorded by Gildas (Higham, 1994). The question then arises as to what caused this renewed military activity on behalf of Wessex. It seems clear to the author that the primary reason for this was the climate upheavals of the 530s and 540s and the associated first pandemic of plague that swept across Europe, which resulted in depopulation and political destabilization. This effect is well documented, and probably resulted from multiple volcanic eruptions with or without some sort of impact event around that time (Degroot, 2016; Newfield, 2016). Yet this effect hardly seems to be considered at all by the academic historical community. The author can see no reason for this, other than a perhaps understandable reluctance to become involved in any way with the more speculative theories outlined in a number of popular works. Yet it seems that the objectivity of these events have a number of implications for academic historians.

  • Gildas’s magnum opus De Excidio Britanniaemust have been written before the first climatic catastrophe, which occurred in 535AD according to reliable tree ring evidence. Otherwise he would surely have included it within his polemic against the moral failure of the rulers of his day. 
  • The fact that this polemic was in some way validated by major external events (either through coincidence or divine action depending on your point of view), may well have been a major reason why Gildas and De Excidio Britanniaewas held in such high authority by his contempories and subsequent writers.
  • The plague hit a weakened Roman population in 542 AD, and would have spread throughout Europe over the next two or three years, judging by the speed of progress of the second pandemic (the Black Death) that has a well established chronology. The Historia Brittonum, regarded by most historians as unreliable for this period, gives the death date, by plague of Maglocunus, one of the rulers castigated by Gildas, as 547AD. This is perhaps three or four years too late, but does (perhaps uncomfortably for some) give an external validation to the Historia Brittonum.
  • The Annales Cambriaegives the death date of Gildas as 570AD, which, on the basis of the above, may be a few years too late. Now Gildas writes that he was born in the year of Mons Badonicus and was 44 years old at the time. Thus supposing he wrote De Excidio Britanniaein 534AD, this gives a date for his birth and the battle of 490AD, which is roughly where many historians would locate it, and would give him an age of, something less than 80 at his death, which does not seem impossible.

Thus, at the very least, a consideration of the effects of the global events of the 530s has the potential to cast some light on the chronology of the mid / late seventh century, and to give a little more confidence in the various annals and chronicles from that period.

N Higham (1994) “The English Conquest – Gildas and Britain in the firth century”, Manchester University Press

D Degroot (2016) “Volcanoes, Comet Crashes, and Changes in the Sun: How Sixth-Century Cooling Transformed the World”, 

T Newfield (2016) “The Global Cooling Event of the Sixth Century. Mystery No Longer?”

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