Have you ever heard the nursery rhyme called ring around the rosie? "Ring around the Rosie. Pocket full of poesy. Ashes, Ashes, we all fall down." This nursery rhyme is actually about a disease from the 14th century that the people called the plague or Black Death. This disease was highly contagious. It spread across Europe. It was so widespread and so deadly that it is estimated to have killed one fourth of all the people in Europe.
If you break down the poem you can actually understand the effects a bit more.
"Ring around the Rosie": Infected people broke out in a rash on their arms and neck that had red ring shaped marks with dark center spot that looked like a rose. They would then get a a high fever, become unconscious, and finally die.
"Pocket full of posey": People carried flowers, often posies, to cover the smell of the dead and dying.
"Ashes, Ashes": People would burn the houses of people with the disease in order to try and stop it. Whole villages were burned down. The sky was dark with the ashes of the burnt buildings.
"We all fall down": The plague filled villages and cities alike with dead and dying victims. People would collapse in the streets and be left lying there. People were afraid to touch them or near them.
Medieval people thought that the plague was a punishment from God. They did not know that fleas transmitted the disease from infected rats to people.
Today we have a vaccine against the plague.