The 1321 leper scare (also known as the lepers' plot) was an alleged conspiracy of French lepers to spread their disease by contaminating well water with their powders and poisons. Lepers were the most abused people during the Middle Ages according to the American Jewish historian Solomon Grayzel; they were thrown out of settlements and treated as wild animals due to the widespread belief that the disease was highly contagious. Jews and Muslims were said to be implicated in the plot, providing an excuse for local authorities to attack both Jewish and leper communities. The hysteria quickly spread to the neighbouring realms, most notably to the Kingdom of Aragon.