Edmund Beaufort, 1st Duke of Somerset (1406 – May 22, 1455), sometimes styled 2nd Duke of Somerset, was an English nobleman and an important figure in the Wars of the Roses and in the Hundred Years' War.
As a young man he was taken prisoner at the Battle of Baugé in 1420 and not released until 1427. He became a commander in the English army in France in 1431. After his re-capture of Harfleur he was named a Knight of the Garter in 1436. After subsequent success he was created Earl of Dorset (1442) and the next year Marquess of Dorset. The following year, (1444) he succeeded his brother John as 4th Earl of Somerset in 1444. During the five year truce from 1444 to 1449 he served as Lieutenant of France.
Although head of the greatest family in the land his inheritance was worth only 300 pounds. By contrast his rival, Richard, Duke of York, had a net worth of 5,800 pounds. King Henry's efforts to compensate Somerset with offices worth 3,000 pounds only served to offend many and as his quarrel with York grew more personal the dynastic situation got worse. Another quarrel with Richard Neville, Earl of Warwick, over his right to enter the lordships of Glamorgan and Morgannwg, may have forced the leader of the younger Nevilles into York's camp.
Somerset's military failures left him vulnerable to criticism from the party led by Richard, Duke of York, and after hostilities began again in 1449 Somerset lost even more territory. By the summer of 1450 the bulk of the English possessions in northern France were in French hands and the focus of the war now turned to Gascony, in the south of France. Here the English were no more successful, losing all by 1453. Somerset's defeat at Castillon in 1453 ended his hopes.
Power had rested with Somerset from 1451 and was virtually monopolized by him until the king went insane and York was named Lord Protector. He imprisoned Somerset in the Tower of London and his life was probably saved only by the king's seeming recovery early in the New Year of 1455, which recovery forced York to surrender his office.
By now York was determined to depose Somerset by one means or another, and in May 1455 raised an army. He confronted Somerset and the king in an engagement known as the First Battle of St Albans which marked the beginning of the Wars of the Roses. Somerset was killed in a last wild charge from the house where he had been sheltering.
Their unlicensed marriage was later pardoned on 7 March 1438, and they had the following children: