Question: How long did the War of the Roses last where Henry Beaufort was an important Lancastrian military commander?
Context: The Wars of the Roses were a series of wars for control of the throne of England fought between supporters of two rival branches of the royal House of Plantagenet: the House of Lancaster (associated with a red rose), and the House of York (whose symbol was a white rose).  The conflict lasted through many sporadic episodes between 1455 and 1487; however, there was fighting before and after this period between the houses.  The power struggle ignited around social and financial troubles following the Hundred Years' War, combined with the mental infirmity and weak rule of Henry VI which revived interest in Richard of York's claim to the throne.  Historians disagree about whether the Wars of the Roses were caused by the structural problems of feudalism or Henry VI's ineffectiveness as king. Duke of Beaufort, a title in the Peerage of England, was created by Charles II in 1682 for Henry Somerset, 3rd Marquess of Worcester, a descendant of Charles Somerset, 1st Earl of Worcester, legitimized son of Henry Beaufort, 3rd Duke of Somerset, a Lancastrian leader in the Wars of the Roses.  The name "Beaufort" refers to a castle in Champagne, France (now Montmorency-Beaufort).  It is the only current dukedom to take its name from a place outside the British Isles. John Clifford, 9th Baron Clifford, (8 April 1435 – 28 March 1461), was a Lancastrian military leader during the Wars of the Roses.  The Clifford family were one of the most prominent families among the northern English nobility of the fifteenth century; and by the marriages of his sisters John Clifford had links to some very important families of the time, including the earls of Devon.  He was orphaned at about twenty years of age when his father was slain at the first battle of the Wars of the Roses, the Battle of St Albans in 1455.  It was probably as a result of his father's death there that John became one of the strongest supporters of Queen Margaret of Anjou, consort of King Henry VI, who ended up as effective leader of the Lancastrian faction.  John Clifford had already achieved prominence in the north where, as an ally of the son of the earl of Northumberland, he took part in a feud against the Neville family, the Percy's natural rivals in Yorkshire.  This consisted of a series of armed raids, assaults and skirmishes, and included an ambush on one of the younger Nevilles' wedding party in 1453.  Historians have seen a direct connection between his involvement in the local feud in the north with the Nevilles, and his involvement in the national struggle against the duke of York, whom the Nevilles were closely allied with in the late 1450s.  Although this was supposedly a period of temporary peace between the factions, Clifford and his allies appear to have made numerous attempts to ambush the Neville and Yorkist lords. Humphrey Stafford, 1st Duke of Buckingham, 6th Earl of Stafford, {'1': ", '2': ", '3': ", '4': "} (15 August 1402 – 10 July 1460) was an English nobleman and a military commander in both the Hundred Years' War and in the Wars of the Roses.  A great-grandson of King Edward III on his mother's side, he inherited his father's earldom of Stafford at an early age.  Through his marriage to a daughter of Ralph, Earl of Westmorland, Humphrey was not only related to the powerful Neville family, but many of the leading aristocratic houses of the time.  Like his father, he joined the English campaign in France and fought for King Henry V; on the King's death he became a leading councillor for the new King, the six-month old Henry VI.  He acted in a peace-making role in the partisan politics of the 1430s, when Humphrey, Duke of Gloucester vied with Cardinal Beaufort for political supremacy, and he was also involved in the arrest of the duke in 1445. Richard Neville, 16th Earl of Warwick (22 November 1428 – 14 April 1471), known as Warwick the Kingmaker, was an English nobleman, administrator, and military commander.  The son of Richard Neville, 5th Earl of Salisbury, Warwick was the wealthiest and most powerful English peer of his age, with political connections that went beyond the country's borders.  One of the leaders in the Wars of the Roses, originally on the Yorkist side but later switching to the Lancastrian side, he was instrumental in the deposition of two kings, a fact which later earned him his epithet of "Kingmaker" to later generations. Henry Beaufort, 3rd Duke of Somerset (26 January 1436 – 15 May 1464) was an important Lancastrian military commander during the English Wars of the Roses.  He is sometimes numbered the 2nd Duke of Somerset, because the title was re-created for his father after his uncle died.  He also held the subsidiary titles of 5th Earl of Somerset, 2nd Marquess of Dorset and 2nd Earl of Dorset. Thomas Courtenay, 5th/13th Earl of Devon (1414–1458) was an English nobleman who was involved in the Wars of the Roses.  His seat was Colcombe Castle, near Colyton, Devon, and later the principal historic family seat of Tiverton Castle after his mother's death.  Much of his life was spent in armed territorial struggle against his near-neighbour in Devon Sir William Bonville of Shute, Devon, at a time when central control over the provinces was weak.  He had been married off as an infant to Margaret Beaufort, granddaughter of John of Gaunt, Duke of Lancaster, and started his career an adherent to the Lancastrian Beaufort party.  On the demise of the Beaufort party he abandoned it in favour of the Duke of York.  When York sought the support of Courtenay's arch-enemy Bonville, Courtenay fell out of favour with York.  The Wars of the Roses led to the deaths and executions of all three of his sons, successively 6th, 7th, and 8th Earls of Devon, and the eventual attainder of his titles and forfeiture of his lands.  The Earldom was however revived in 1485 for his distant cousin Sir Edward Courtenay, KG, (d. 1509), third in descent from his great-uncle.  The ordinal number given to the early Courtenay Earls of Devon depends on whether the earldom is deemed a new creation by the letters patent granted 22 February 1334/5 or whether it is deemed a restitution of the old dignity of the de Redvers family.  Authorities differ in their opinions, and thus alternative ordinal numbers exist, given here. Baron Raglan, of Raglan in the County of Monmouth, is a title in the Peerage of the United Kingdom.  It was created in 1852 for the military commander Lord FitzRoy Somerset, chiefly remembered as commander of the British troops during the Crimean War.  Somerset was the youngest son of Henry Somerset, 5th Duke of Beaufort (see Duke of Beaufort for earlier history of the family).  His second but eldest surviving son, the second Baron, served as a Lord-in-Waiting (government whip in the House of Lords) from 1866 to 1868 in the Conservative administrations of the Earl of Derby and Benjamin Disraeli.  He was succeeded by his son, the third Baron.  He held office as Under-Secretary of State for War between 1900 and 1902 in the Conservative government of Lord Salisbury.  His eldest son, the fourth Baron, was a soldier and also served as Lord Lieutenant of Monmouthshire.  The fifth Baron was active in the House of Lords but lost his seat in the upper chamber of parliament after the passing of the House of Lords Act 1999.  s of 2012 the title is held by the fourth Baron's third but second surviving son, the sixth Baron, who succeeded in 2010.  As a descendant of the fifth Duke of Beaufort, Lord Raglan is also in remainder to this peerage and its subsidiary titles. Thomas Beaufort, 1st Duke of Exeter, KG (c. 1377 – c. 31 December 1426) was an English military commander during the Hundred Years' War, and briefly Chancellor of England.  He was the third of the four children born to John of Gaunt, Duke of Lancaster, and his mistress Katherine Swynford.  To overcome their problematic parentage, his parents were married in 1396, and he and his siblings were legitimated on two separate occasions, in 1390 and again in 1397.  He married the daughter of Sir Robert Neville (d. 1413) of Hornby, Margaret Neville, who bore him one son, Henry Beaufort.  However, the child died young. The Battle of Hedgeley Moor, 25 April 1464, was a battle of the Wars of the Roses.  It was fought at Hedgeley Moor, north of the village of Glanton in Northumberland, between a Yorkist army led by John Neville, Lord Montagu and a Lancastrian army led by Henry Beaufort, Duke of Somerset.  The battle ended in a Yorkist victory.
Answer: between 1455 and 1487