The Plague of Athens was an epidemic that devastated the city-state of Athens in ancient Greece during the second year of the Peloponnesian War when an Athenian victory still seemed within reach. The plague killed an estimated 75,000 to 100,000 people, around 25% of the population, and is believed to have entered Athens through Piraeus, the city's port and sole source of food and supplies. Thucydides, an Athenian survivor, wrote that much of the eastern Mediterranean also saw an outbreak of the disease, albeit with less impact.