Ponca City, We Love You writes: "In 536 Byzantine historian Procopius wrote that "a most dread portent took place. For the sun gave forth its light without brightness... and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear." Now palaeoclimatologist Keith Briffa and an international team of collaborators have found the characteristic fingerprint of a volcanic eruption in layers of ice in the Greenland and Antarctic ice sheets, narrowly dated to around 533-536 and the amount of sulphate they found implies that the eruption was even bigger than that of Tambora in Indonesia in 1815, perhaps releasing as much as 40% more dust making the event "the most severe volcanic cooling event in the Northern Hemisphere in the past 2,000 years". Some have suggested that consequences of the erpuption were more dramatic than mere crop failure and overcast skies. Around 541, a plague pandemic rampaged from southern Asia to Denmark, wreaking havoc in the Byzantine Empire and possibly killing about 40% of the inhabitants of its capital Constantinople."