Final answer:
Emperor Justinian's reign was affected by the Plague of Justinian, which eliminated a significant portion of the population in the eastern Mediterranean region.
Step-by-step explanation:
Emperor Justinian's reign was affected by the Plague of Justinian. From 541 to 750 A.D., this outbreak of what was likely a bubonic plague eliminated one-quarter to one-half of the human population in the eastern Mediterranean region. The population in Europe declined by 50 percent during this outbreak.