William III de Ferrers, 5th Earl of Derby (c. 1193 – 28 March 1254) of Chartley Castle in Staffordshire, was an English nobleman and major landowner, unable through illness to take much part in national affairs. From his two marriages, he left numerous children who married into noble and royal families of England, France, Scotland and Wales. Origins He was the son and heir of William de Ferrers, 4th Earl of Derby (c. 1168 – c. 1247), by his wife Agnes de Kevelioc, a daughter of Hugh de Kevelioc, 5th Earl of Chester (by his wife Bertrada de Montfort). Career In 1230 he accompanied King Henry III to France and attended Parliament in London in the same year. Like his father, he suffered from gout from youth and after the 1230s took little part in public affairs, travelling always in a litter. He was accidentally thrown from his litter into the River Great Ouse while crossing a bridge at St Neots in Huntingdonshire and, although he escaped death, never recovered from the effects of the accident. He succeeded to the title of his father in 1247, but only lived another seven years, dying on 28 March 1254. Landholdings Unable to play any part at court or at war, he followed his father in managing the family's landholdings. Their original lands were centred on Tutbury Castle, stretching beyond Staffordshire into the south of Derbyshire and the west of Nottinghamshire. The death in 1232 of his uncle Ranulf de Blondeville, 6th Earl of Chester, brought him vast new estates, including Chartley Castle in Staffordshire, much of Lancashire between the Rivers Ribble and Mersey and many manors in Northamptonshire and Lincolnshire. He continued the policy of encouraging the growth of towns and markets, exploiting the forests of Needwood and Duffield Frith, and taking advantage of rising prices in commodities and land values. By the time of his death his income placed him among the top six English nobles, but he also left his son considerable debts. Marriages & issue He married twice: To Sybil Marshal He married (1st) Sibyl Marshal, a daughter of William Marshal, 1st Earl of Pembroke, by his wife Isabel de Clare, 4th Countess of Pembroke, by whom he had seven daughters: Agnes de Ferrers (d. 11 May 1290), who married (as his second wife) William de Vesci (d.1253); Isabel de Ferrers (died before 26 November 1260), who married (1)