Between 1347 and 1350, a terrible disease called the bubonic plague swept in from Asia and spread across Europe. The plague was carried by rat fleas that feasted on people's blood. It killed almost everyone it infected. Perhaps 20 million people throughout Europe perished. One third of the population of England died. It was known as the Black Death.

The marketplace was alive with noises and smells on the morning of market day. Pigs were a nuisance, however. Most townspeople kept them as they were cheap and a good source of food. But they were often let out into the streets to search for food.

The streets of a medieval town were dirty and smelly. Open drain channels ran along the sides or down the middle of the streets. People often threw dirty water and their waste out of their windows on to the street below. Many people drew water from rivers, which were full of muck and thick with germs. Diseases were common, but the Black Death was far worse than usual.

The plague spreads

The name "Black Death" might have come from the black spots that appeared on victims. The disease was carried by fleas that lived on black rats—although no one knew that at the time—and these rats were commonly found in crowded, filthy places.

People fled from infected towns—spreading the disease as they went. There was no cure. The dead bodies were collected on carts in the night. The population of whole towns and villages was wiped out.

Doctors in the Middle Ages did not understand disease. They had no knowledge of germs. When the Black Death came, they could not cure it. In fact no one knew what had caused the plague. Some said it was to do with the movements of the planets. Others blamed "enemies"—for example, the Jews—for poisoning wells. Many thought that the plague was simply a punishment from God.