Whose son's death brought titles to Edward III's most trusted captain?
Henry of Grosmont, 1st Duke of Lancaster Henry of Grosmont, 1st Duke of Lancaster, 4th Earl of Leicester and Lancaster, KG (c. 1310 – 23 March 1361), also Earl of Derby, was a member of the English nobility in the 14th century, and a prominent English diplomat, politician, and soldier. The son and heir of Henry, 3rd Earl of Lancaster, and Maud Chaworth, he became one of Edward III's most trusted captains in the early phases of the Hundred Years' War and distinguished himself with victory in the Battle of Auberoche. He was a founding member and the second Knight of the Order of the Garter in 1348, and in 1351 was created duke. An intelligent and reflective man, Grosmont taught himself to write and was the author of the book "Livre de seyntz medicines", a highly personal devotional treatise. He is remembered as one of the founders and early patrons of Corpus Christi College, Cambridge, which was established by two of the guilds of the town in 1352.
Roger Mortimer, 1st Earl of March Roger Mortimer, 3rd Baron Mortimer, 1st Earl of March (25 April 1287 – 29 November 1330), was an English nobleman and powerful Marcher lord who gained many estates in the Welsh Marches and Ireland following his advantageous marriage to the wealthy heiress Joan de Geneville, 2nd Baroness Geneville. In November 1316, he was appointed Lord Lieutenant of Ireland. He was imprisoned in the Tower of London in 1322 for having led the Marcher lords in a revolt against King Edward II in what became known as the Despenser War. He later escaped to France, where he was joined by Edward's queen consort Isabella, whom he took as his mistress. After he and Isabella led a successful invasion and rebellion, Edward was subsequently deposed; Mortimer allegedly arranged his murder at Berkeley Castle. For three years, Mortimer was "de facto" ruler of England before being himself overthrown by Edward's eldest son, Edward III. Accused of assuming royal power and other crimes, Mortimer was executed by hanging at Tyburn.