Simon de Montfort, 6th Earl of Leicester (1208? – 4 August 1265), also called Simon de Munford and sometimes referred to as Simon VI de Montfort to distinguish him from other Simons de Montfort, was a French nobleman who inherited the title and estates of the earldom of Leicester in England. He led the rebellion against King Henry III of England during the Second Barons' War of 1263–4, 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.
John of Gaunt, 1st Duke of Lancaster, KG (6 March 1340 – 3 February 1399) was a member of the House of Plantagenet, the third surviving son of King Edward III of England and Philippa of Hainault. He was called "John of Gaunt" because he was born in Ghent, then rendered in English as Gaunt. When he became unpopular later in life, scurrilous rumours and lampoons circulated that he was actually the son of a Ghent butcher, perhaps because Edward III was not present at the birth. This story always drove him to fury.As a younger brother of Edward, Prince of Wales (Edward, the Black Prince), John exercised great influence over the English throne during the minority of his nephew, Richard II, and during the ensuing periods of political strife, but was not thought to have been among the opponents of the king.John of Gaunt's legitimate male heirs, the Lancasters, included Kings Henry IV, Henry V, and Henry VI. His other legitimate descendants included, by his first wife, Blanche, his daughters Queen Philippa of Portugal and Elizabeth, Duchess of Exeter; and by his second wife, Constance, his daughter Queen Catherine of Castile. John fathered five children outside marriage, one early in life by a lady-in-waiting to his mother, and four surnamed "Beaufort" (after a former French possession of the Duke) by Katherine Swynford, Gaunt's long-term mistress and third wife. The Beaufort children, three sons and a daughter, were legitimised by royal and papal decrees after John and Katherine married in 1396; a later proviso that they were specifically barred from inheriting the throne, the phrase excepta regali dignitate (English: except royal status), was inserted with dubious authority by their half-brother Henry IV. Descendants of this marriage included Henry Beaufort, Bishop of Winchester and eventually Cardinal; Joan Beaufort, Countess of Westmorland, grandmother of Kings Edward IV and Richard III; John Beaufort, 1st Earl of Somerset, the grandfather of Margret Beaufort, the mother of King Henry VII; and Joan Beaufort, Queen of Scots, from whom are descended, beginning in 1437, all subsequent sovereigns of Scotland, and successively, from 1603 on, the sovereigns of England, of Great Britain and Ireland, and of the United Kingdom to the present day. The three succeeding houses of English sovereigns from 1399—the Houses of Lancaster, York and Tudor—were descended from John through Henry Bolingbroke, Joan Beaufort and John Beaufort, respectively.Lancaster's eldest son and heir, Henry Bolingbroke, Duke of Hereford, was exiled for ten years by King Richard II in 1398 as resolution to a dispute between Hereford and Thomas de Mowbray, Duke of Norfolk. When John of Gaunt died in 1399, his estates and titles were declared forfeit to the crown as King Richard II named Hereford a traitor and changed his sentence to exile for life. Henry Bolingbroke returned from exile to reclaim his inheritance and depose Richard. Bolingbroke then reigned as King Henry IV of England (1399–1413), the first of the descendants of John of Gaunt to hold the throne of England. Due to some generous land grants, John was not only one of the richest men in his era, but also one of the wealthiest men to have ever lived. Taking into account inflation rates, John was worth a modern equivalent of $110 billion, making him the sixteenth richest man in history.