de Montfort refers to Simon de Montfort, a prominent figure in 13th-century England. He was a French nobleman who became the Earl of Leicester and played a crucial role in the English civil war known as the Second Barons' War. His leadership and reforms aimed to limit the power of the monarchy and increase the influence of the barons. Simon de Montfort is best known for calling the first elected parliament in 1265, which included not just nobles but also commoners. This event marked a significant step towards the development of modern parliamentary democracy in England, influencing future governance structures.