Montfort, Simon de, Earl of Leicester, 1208?-1265 (Personal Name)

Jobson, Adrian. The first English revolution, 2012: title page (Simon de Montfort) page ix (the years 1258-67 witnessed a bitter political struggle between King Henry III and his baronage, led by his brother-in-law Simon de Montfort, Earl of Leicester; slain at Evesham in August 1265)

Wikipedia (English), February 5, 2016 (Simon de Montfort, 6th Earl of Leicester (c. 1208 - 4 August 1265), also called Simon de Munford and sometimes referred to as Simon V de Montfort to distinguish him from other Simons de Montfort, was a French nobleman who arrived in England in 1229, with some education but no knowledge of English; inherited the title and estates of the earldom of Leicester in England; led the rebellion against King Henry III of England during the Second Barons' War of 1263-64, and subsequently became de facto ruler of England; during his rule, de Montfort called two famous parliaments: the first stripped the King of unlimited authority, the second included ordinary citizens from the towns; for this reason, Montfort is regarded today as one of the progenitors of modern parliamentary democracy; after a rule of just over a year, Montfort was killed by forces loyal to the King in the Battle of Evesham, August 4, 1265)

Ambler, S. The song of Simon de Montfort, 2019.