The main well dressing commemorates the granting of Magna Carta at Runnymede on June 15th 1215 where it was sealed - not signed - by King John and witnessed by twenty five barons. Magna Carta or The Great Charter was drawn up after a rebellion by the barons because the king had demanded heavy taxes to finance his unsuccesful wars in France. It enshrined the rights, privileges and liberties of the nobles and clergy and limited the power of the Crown.
Magna Carta was written in medieval Latin on parchment made from dried sheepskin and the words were often abbreviated to save space on the parchment. Many copies were made and sent out to bishops and sheriffs all over England. Only four of these copies survive, two in the British Library, one in Lincoln and one in Salisbury. I've seen the one in Salisbury Cathedral and it's much smaller than I'd imagined. It's an iconic document and inspired the American Declaration of Independence of 1775 and the 1948 UN Charter for Human Rights. Only three of the original clauses in Magna Carta are still law. One defends the freedom and rights of the English church, another confirms the liberties and customs of London and other towns, and the third paved the way for trial by jury by stating that no man could be arrested, imprisoned or have their possessions taken away except by “the lawful judgement of his equals or by the law of the land”
This is the seal of King John who was the younger brother of Richard the Lionheart. John succeeded to the throne of England after Richard's death in 1199. John is also of course the villain, along with the Sheriff of Nottingham, in all the stories of Robin Hood. So there we are - that's the end of today's history lesson:)