Throughout history, the succession of wars, social conflicts, economic crises, natural disasters, and plagues has led people to perceive certain years or periods as particularly dreadful to live through or be born into. This perception has always prompted the recurring question: are we living in one of the worst periods in history? And looking back, what was the worst year of all time?  

Historians and enthusiasts of such studies have asked themselves the same question, identifying one year in particular: 536 AD. While history has witnessed many terrible years—such as the Black Death of 1347-48 or the Thirty Years' War from 1618-48—what makes 536 stand out?  

The main reasons lie in a series of catastrophic events that occurred that year (with devastating consequences in the following years) and had an almost global impact. A sequence of volcanic eruptions—primarily in Iceland and across the Northern Hemisphere—devastated surrounding territories and triggered dramatic climate changes across much of Europe. The sky was shrouded in thick clouds and toxic fumes (acidic volcanic dust), significantly lowering temperatures. In some cases, it even snowed during the summer—similar to what would happen later in the 14th century. These extreme conditions led to widespread crop failures, resulting in severe hardship, increasing plagues, and crises across various kingdoms of the 6th century.  

Procopius described these ominous events with the following words: "...the sun, lacking its usual brightness and resembling the moon, remained hidden from human sight for most days; stripped of its ordinary radiance, it shone dimly and darkly, an omen—soon proven true—of impending war, plague, famine, and every other calamity..."  

The historian was referring to what later became known as the "Justinian Plague" or "Plague of Justinian," a massive outbreak of bubonic plague that erupted in 536-37. This epidemic actively contributed to the decimation of the population within the Byzantine Empire, which was already weakened by harsh climatic conditions and ongoing wars.