John I of England was king from 1199 to 1216. He is often remembered for his conflicts with the nobility and his failure to maintain the territories in France that his father, Henry II, had acquired. His reign was marked by heavy taxation and disputes with powerful barons, leading to widespread discontent. In 1215, the barons rebelled against him, resulting in the signing of the Magna Carta, a document that limited the king's power and established certain legal rights. This agreement is considered a foundational moment in the development of constitutional law in England and influenced future democratic principles.