William Ferrers, 3rd Lord Ferrers

Arms of Ferrers, Baron Ferrers of Groby: Gules, seven mascles or conjoined 3:3:1. These are the arms of de Quincy, adopted in lieu of his paternal arms (Vairy or and gules) by William Ferrers, 1st Baron Ferrers of Groby (1272–1325). He was the son and heir of Sir William de Ferrers (1240–1287) of Groby, the younger son of William de Ferrers, 5th Earl of Derby (by his second wife Margaret de Quincy, daughter and heiress of Roger de Quincy, 2nd Earl of Winchester (c. 1195 – 1264)) who founded the line of Baron Ferrers of Groby, having been given Groby Castle by his mother Margaret de Quincy. William Ferrers, 3rd Baron Ferrers of Groby (1333–1371) was a Leicestershire-based nobleman in fourteenth-century England who took part in some of the major campaigns of the first part of the Hundred Years' War. The eldest of two sons to Henry Ferrers, 2nd Baron Ferrers of Groby (d. 1343), and Isabel de Verdun, daughter of Theobald de Verdun, 2nd Baron Verdun, William was ten years old when he succeeded his father to the Barony.

Early life William Ferrers was born at the family caput of Newbold Verdon, Leicestershire, on 28 February 1333, and received baptism the same day. Two years after his father's death, an allowance of £50 was remitted by the king and council for his care (later, in 1349, converted into a grant of the manors of Stoke on Tern, Wootton and Hethe). As he was still a minor, custody of his patrimony was shared between King Edward III's queen, Philippa, and his son, Edward. William Ferrers grew up as the bubonic plague was ravaging the country, and like everywhere else, this had a severely deleterious effect on the Ferrers family's finances. Almost entire villages were being wiped out (for example, that of Hethe, one of the Ferrerses' manors, lost 21 out of its 27 villeins) which meant whole crops were being lost and the value of those manors collapsed. With her, William had a son and two daughters; she had died by 1368. His next marriage was to another Margaret, the daughter of Henry de Percy, 2nd Baron Percy, the widow of Sir Robert de Umfraville. This marriage was childless and she survived Ferrers by four years.

Ferrers' last will and testament was written in July 1368, in which he requested interment in the family crypt at Ulverscroft Priory. He died in Stebbing, Essex, during the night of 8 January 1371. He was succeeded by his only son from his first marriage, Henry, who inherited the barony.