The Barons' Revolt was a conflict in England during the early 13th century, primarily between a group of rebellious barons and King John of England. The barons were unhappy with King John's heavy taxation and his failure to uphold the rights and privileges granted to them. This discontent led to a series of confrontations, culminating in the barons capturing London in 1215. The revolt ultimately resulted in the signing of the Magna Carta, a foundational document that limited the powers of the monarchy and established certain legal rights for the barons and, by extension, all free men. This agreement marked a significant step towards the development of constitutional law in England.