Question: Whose son's death brought titles to Edward III's most trusted captain?

The House of Lancaster was the name of two cadet branches of the royal House of Plantagenet.  The first house was created when Henry III of England created the Earldom of Lancasterfrom which the house was namedfor his second son Edmund Crouchback in 1267.  Edmund had already been created Earl of Leicester in 1265 and was granted the lands and privileges of Simon de Montfort, 6th Earl of Leicester, after de Montfort's death and attainder at the end of the Second Barons' War.  When Edmund's son Thomas, 2nd Earl of Lancaster, inherited his father-in-law's estates and title of Earl of Lincoln he became at a stroke the most powerful nobleman in England, with lands throughout the kingdom and the ability to raise vast private armies to wield power at national and local levels.  This brought himand Henry, his younger brotherinto conflict with their cousin Edward II of England, leading to Thomas's execution.  Henry inherited Thomas's titles and he and his son, who was also called Henry, gave loyal service to Edward's sonEdward III of England. <SEP> 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.  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.  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. <SEP> Richard II (6 January 1367 – c. 14 February 1400), also known as Richard of Bordeaux, was King of England from 1377 until he was deposed on 30 September 1399.  Richard, a son of Edward, the Black Prince, was born in Bordeaux during the reign of his grandfather, Edward III.  His father was Prince of Aquitaine.  Richard was the younger brother of Edward of Angoulême, upon whose death Richard, at three years of age, became second in line to the throne after his father.  Upon the death of Richard's father prior to the death of Edward III, Richard, by primogeniture, became the heir apparent to the throne.  With Edward III's death the following year, Richard succeeded to the throne at the age of ten. <SEP> King Duncan is a fictional character in Shakespeare's "Macbeth."  He is the father of two youthful sons (Malcolm and Donalbain), and the victim of a well-plotted regicide in a power grab by his trusted captain Macbeth.  The origin of the character lies in a narrative of the historical Donnchad mac Crinain, King of Scots, in Raphael Holinshed's 1587 "The Chronicles of England, Scotland, and Ireland," a history of Britain familiar to Shakespeare and his contemporaries.  Unlike Holinshed's incompetent King Duncan (who is credited in the narrative with a "feeble and slothful administration"), Shakespeare's King Duncan is crafted as a sensitive, insightful, and generous father-figure whose murder grieves Scotland and is accounted the cause of turmoil in the natural world.