Dictionary of National Biography, 1885-1900/Darcy, John
DARCY, JOHN (d. 1347), baron, younger son of Norman, lord Darcy of Nocton, Lincolnshire, who died in 1296, and brother of Philip, the eighth and last Baron Darcy of Nocton, served in Scotland under Edward I, was sheriff of the counties of Nottingham and Derby under Edward II, and in 1327 was sheriff of Yorkshire. He was appointed lord justice of Ireland by Edward II, reappointed by Edward III, and in 1341 received a grant of his office for life. In 1333 he was with the king in Scotland, and about two years later wasted Bute and Arran. In 1337 he was employed in embassies to Scotland and France. He served in Flanders, in Brittany (Knighton), and in the war with France of 1346. He was steward of the king's household, and held a life-grant of the office of constable of the Tower. He died 30 May 1347. He married, first, Emmeline, daughter of Walter Heron, and granddaughter and heiress of William, baron Heron, who died in 1296, by whom he had two sons and a daughter; secondly, Joan, daughter of Richard de Burgh, earl of Ulster. His lands lay chiefly in Yorkshire and Lincolnshire, and he is generally styled Lord Darcy of Knaith, one of his manors, to distinguish him from the elder branch of the house. He was summoned to parliament first as ‘John Darcy le Cosin,’ and after the death of his elder brother's heir as John Darcy.
[Dugdale's Baronage, i. 371; Nicolas's Peerage, ed. Courthope, 141; H. Knighton, Twysden, col. 1581.]