Thomas, Earl of Lancaster (1280 - March 22, 1322) was one of the leaders of the barons opposed to Edward II of England.
Thomas was the eldest son of Edmund Crouchback and thus a grandson of Henry III of England. From his father he inherited the earldoms of Lancaster, Leicester, and Derby. By his marriage to Alice de Lacy, daughter of Henry de Lacy, he became earl of Lincoln and Salisbury upon the death of his father-in-law in 1311.
Lancaster was one of the Lords Ordainers who demanded the banishment of Piers Gaveston and the establishment of a baronial oligarchy. His private army helped separate the king and Gaveston, and Lancaster was one of the 'judges' who convicted Gaveston and saw him executed.
After the disaster at Bannockburn in 1314, Edward submitted to Lancaster, who in effect became ruler of England. He attempted to govern for the next four years, but was unable to keep order or prevent the Scots from raiding and retaking territory in the North. In 1318 a new faction of barons arose, and Lancaster was deposed from office.
The new leadership, eventually headed by the Despensers, proved no more popular with the baronage, and in 1321 Lancaster was again at the head of a rebellion. This time, however, he was defeated at the Battle of Boroughbridge, and afterwards convicted of treason and executed near the Pontefract Castle.
Upon his death his titles and estates were forfeited, but in 1323 his younger brother Henry successfully petitioned to take possession of the earldom of Leicester. In 1326 or 1327 Parliament posthumously reversed Thomas' conviction, and Henry was further permitted to take possession of the earldom of Lancaster.
Thomas became venerated as a martyr and saint within a few months of his death. Hagiographies were written about him, and Edward III wrote 3 times to the Pope requesting his canonization. He was never canonized, though rumors to that effect arose in the 1390s, when his cult experienced something of a revival.
- C. Given-Wilson, "Richard II, Edward II, and the Lancastrian Inheritance", English Historical Review, 109 (1994), 553-571