The year 536 AD marks what some researchers now call the coldest year in the last two millennia. A combination of impact events and volcanic eruptions created what he describes as a perfect storm, one that essentially launched the Dark Ages. For the next three to four hundred years, particularly across Northern Europe where most of the historical records originate, there was broad-scale social collapse. Agricultural failures repeated over six to seven years. People couldn't get enough to eat, their immune systems weakened from malnutrition, and they became vulnerable to opportunistic diseases. Then in 542 AD, the Justinian Plague arrived and wiped out an estimated half the population of Europe. This wasn't just a bad decade. It was a cascading systemic failure triggered by cosmic and volcanic forcing, recorded in ice cores, tree rings, and the written accounts of those who survived it.