The Black Death came from Asia and devastated Europe in the mid-14th century, so-called because of the black spots (ecchymosis) that appeared on the bodies of the victims was transmited by rats and fleas. It took two main forms. The bubonic variety was physically the most abhorrent and painful, manifesting itself in the eruption of stinking boils and pustules and putrifcation of the victim's felsh. This form was not invariably fatal. The pneumonic variety attacked the lungs and usually caused death within 48 hours.

The first signs were large boils in the groin or under the arm. Black marks then appeared, which spread across the arms or thighs. . For three to four days the sufferer lay almost insensible with pain and fever and gave off a revolting smell. When the boils finally burst, it let out a foul smelling black pus. Death brought a blessed relief from this pitiless suffering.

The plague is estimated by the historian Philip Zeigler to have killed about one third of the European population. Panic became widespread: groups of flagellants roamed from place to place hoping to stay the disease by acts of penance. Other people attacked their Jewish neighbors, accusing them of having poisoned the wells. Economic hardship and a shortage of labout resulting from the Black Death was a contributing cause of rebellions such as the Peasants' Revolt (1381) in England.

The name does not appear before the 16th century and comes from the dark skin haemorrage (ecchymosis). Coughing and sneezing were accompaning symptoms and may have given rise to the nursery rhyme.

Ring a ring o' roses,
A pocket full of poses,
A-toshoo! A-tishoo!
We all fall down.