Grosseteste, Robert, c.1175-1253, English prelate. Educated at Oxford and probably also at Paris, he became one of the most learned men of his time. He taught at Oxford and later, as rector, made the university an important center of learning. In 1224 he became lector of the Franciscans there and founded the Oxford Franciscan school, which profoundly influenced medieval thought. His most illustrious pupils, Adam Marsh and Roger Bacon, continued Grosseteste's work at Oxford after he was made (1235) bishop of Lincoln, then the most populous see of England.

As bishop, Grosseteste was an indefatigable administrator and zealous reformer, visiting the monasteries, assigning suitable candidates to parish offices, and preaching to the people. Grosseteste fought for the maintenance of the Magna Carta. He thwarted efforts of Henry III to control ecclesiastical appointments, and as a member of the baronial council he supported the reforms of Simon de Montfort (1208-65). Grosseteste did not hestitate to censure Pope Innocent IV for his excessive exactions and for appointing foreigners to rich English benefices; he also attacked the Curia for its corruption and indolence. Some historians see in Grosseteste's protests against Rome an influence upon Wyclif and a foreshadowing of the Reformation.

Grosseteste was a prolific scholar. He knew Greek and probably Hebrew; his translations of, and commentaries on, Aristotle served as a foundation for the scholasticism of Albertus Magnus and Thomas Aquinas. His prolific writing included treatises on physics, optics, light, motion, color, mathematics, astronomy, psychology, pastoral works, and polemical poems in French for the laity. For 50 years after his death he was venerated in his diocese as a saint. In recent years he has been accounted one of the early practitioners of modern scientific method.