Historians cite 536 AD as one of the most difficult years in human history

Historians describe the year 536 AD as one of the most severe periods humanity has faced. Massive volcanic eruptions released dense clouds of ash and sulfur into the atmosphere, blocking much of the sunlight and driving down global temperatures. Byzantine historian Procopius wrote that the sun appeared pale throughout the year, resembling the moon. Across wide stretches of Europe, the Middle East and Asia, sunlight fell well below normal levels. In China, summer snow was reported and crops were damaged in many regions. Ice and tree-ring samples from Greenland and the Alps contain volcanic glass fragments traced to Iceland. Around 539–540, the Ilopango eruption in El Salvador added further pollutants to the atmosphere. The Northern Hemisphere endured one of the coldest stretches of the past two millennia, with European summer temperatures dropping by 1.5 to 2.5 degrees Celsius. Prolonged crop failures brought famine and weakened immune systems across affected populations.