The Earl of Paunchley was a 15th Century Muggle nobleman from Poppleton, England, who made the lives of those around him miserable with his demands (BoS).
The Earl punished anyone who disobeyed him, so in the year 1484 when young Edmund Gaddlegate broke his leg and could not attend a jousting tournament, the Earl had the boy and his mother dragged to his castle. Edmund was promptly tied to a horse, and the other knights were ordered to joust with him. Disgusted at the idea of attacking a defenseless child, the other knights departed, so the furious Earl of Paunchley decided that he would joust with the boy instead.
This cruel display irritated a witch in the crowd - Hannah Cockleford - and she decided to teach the so-called nobleman a lesson. As her rode with his spear pointed at Edmund, the witch cast a strong Shield Charm between them, knocking the Earl backwards. His horse landed on top of him, and while that calamity did not kill him, the accident affected his mind. Afterward he believed himself to be a donkey called "Hairy Cyril" (BoS).