Sir John Cavendish of Cavendish (c. 1346 – 15 June 1381) was an English judge from Cavendish, Suffolk, England. He and the village gave the name Cavendish to the aristocratic families of the Dukedoms of Devonshire, Newcastle and Portland.
John Cavendish was descended from the Norman Robert de Gernon, who lived during the reign of Henry I and who gave a large amount of property to the Abbey of Gloucester. Robert's son, also called Robert de Gernon, of Grimston Hall, Suffolk, married the heiress of John Potton of Cavendish and obtained a landed estate in the lordship and manor of Cavendish. In consequence, his four sons exchanged their father's name for that of the estate each inherited. John was the eldest of the sons.
One of John's brothers, Roger Cavendish, was the ancestor of Thomas Cavendish known as "The Navigator".
Sir John Cavendish became a lawyer and was appointed as a Justice of the Common Pleas in 1371 and Chief Justice of the King's Bench in 1372. He was also elected Chancellor of the University of Cambridge.
As Chief Justice he was obliged to suppress the Peasants' Revolt in 1381. Although Wat Tyler, the leader of the revolt was struck down by William Walworth, mayor of London, during negotiations on 15 June, John Cavendish, the second son of the Chief Justice, gave the finishing stroke to Wat Tyler, the lord mayor having only wounded him in the neck. As a result of this, the father, Sir John Cavendish, was pursued by the peasants. He reached St. Mary's Church, Cavendish, where he pleaded sanctuary by grasping the handle of the church door. This was to no avail, however, and he was taken to the market place at Bury St. Edmunds and beheaded by a mob led by Jack Straw on 15 June 1381. He was buried in Bury St. Edmunds.
St. Mary's Church, Cavendish, benefited from a large bequest made by Sir John and had its chancel refurbished.
- The father of Sir John Cavendish (senior) was not Robert de Gernon, it was Roger Gernon of Grimston Hall. Roger Gernon was born in Stansted in 1274. His father Geoffrey was born at the Gernon Lordhip of Bakewell in 1231. The first family seat of the Gernons was at Stansted Mountfitchet in Essex. They held the Lordship of Bakewell, Chatsworth which became the seat of the Dukes of Devonshire,that ran adjacent to Bakewell. The Gernons also held the Lordship of Lexden in Essex. Sir John Cavendish was born long before 1346, it was more likely his son, John who was born then.
- Sir John Sainty (comp.) The Judges of England, 1272-1990: a list of the judges of the Superior courts (Selden Society: Supplementary Series 1993), 88.
- Notices of the Manor of Cavendish, in Suffolk, and of the Cavendish Family while possessed of that Manor. By Thomas Ruggles, Esq. F. A. S. Read 3 May 1792. in Archaeologia, or, Miscellaneous tracts relating to antiquity, Volume XI
- Rootsweb: Descendants of Luke Dillon and Susannah Garrett: PAFG189: John de Cavendish and Alice Odyngseles
- Stirnet: GZmisc01 (subscription required) (shows Cavendish's place in the de Gernon family)
- Stirnet: Cavendish01 (subscription required) (shows Cavendish as the patriarch of the Cavendish family)