Justinian's Flea: The First Great Plague and the End of the Roman Empire

The Emperor Justinian reunified Rome's fractured empire by defeating the Goths and Vandals who had separated Italy, Spain, and North Africa from imperial rule. At his capital in Constantinople, he built the world's most beautiful building, married its most powerful empress, and wrote its most enduring legal code, seemingly restoring Rome's fortunes for the next five hundred years. Then, in the summer of 542, he encountered a flea. The ensuing outbreak of bubonic plague killed five thousand people a day in Constantinople and nearly killed Justinian himself.