The Plague of Justinian

541 CE — Eastern Mediterranean, Byzantine Empire

Today: The eastern Roman Empire (capital Constantinople)

Just as the eastern Roman emperor Justinian was reconquering Italy and North Africa — nearly restoring the old Roman world — bubonic plague swept his empire, killing perhaps a third of its people and gutting its armies and treasury. The reconquest collapsed, and with it the last real chance to reunite the Roman Mediterranean. A pandemic had quietly redrawn the map of Europe, and demography had overruled strategy.

Worth knowing: This was history's first recorded bubonic plague — the same disease as the later Black Death — and its dead so overwhelmed Constantinople that bodies were reportedly stacked inside the towers of the city walls.

Pattern: Pandemic — A pathogen spreads through a population and reshapes its demography, economy, and beliefs at once.

Entry 91 of 240 in Precedent, a walk through the whole human story in order.