Poitiers, Diane de: see Diane de Poitiers.

Poitiers, city (1990 pop. 82,507), capital of Vienne dept., W central France, on the Clain River. The ancient capital of Poitou, it is now an industrial, agricultural, and communications center. Poitiers's industries include metallurgy, machine building, printing, and the manufacture of chemicals and electrical equipment. The city was the capital of the Pictons, a Gallic people, and under the Romans was called Limonum. Christianized early in Roman times, it was a stronghold of orthodoxy under its first bishop, St. Hilary of Poitiers (4th cent.), and, because of its important monasteries, was a great religious center of Gaul. A residence of Visigoth kings, the city was captured (507) by the Franks under Clovis I. In 732, Charles Martel turned the Muslim tide by defeating the Saracens between Poitiers and Tours. Poitiers was often sacked by the Normans in the 9th cent. It was twice under English rule (1152-1204, 1360-72) and was the location of the brilliant court of Eleanor of Aquitaine. At Poitiers in 1356, Edward the Black Prince defeated and captured John II of France and his son, Philip the Bold of Burgundy. Charles VII had his court in Poitiers from 1423 to 1436 and founded a university there in 1432. In the Wars of Religion (1562-98) the city was unsuccessfully besieged (1568) by the Huguenots; in 1577 the Peace of Bergerac (also known as the Edict of Poitiers) was signed there granting religious freedom (see Religion, Wars of). Architecturally, Poitiers is one of the most interesting cities in Europe. There are Roman amphitheaters and baths, the baptistery of St. John (4th-12th cent.), the Cathedral of St. Pierre (12th-14th cent.), the courthouse (12th-15th cent., formerly a royal residence), as well as numerous other churches and late medieval and Renaissance residences.

Hilary of Poitiers, Saint, c.315-367?, bishop of Poitiers from c.350, Doctor of the Church. A convert from paganism, he distinguished himself as a supporter of Athanasius against Arianism. For his zeal he was exiled (c.356). After his return (360) he aided Pope Liberius in the attempted purge of Arianism in the West. He wrote many theological works, mostly against the Arians, including the historically invaluable De synodis and the De trinitate (tr. by Stephen McKenna, 1954). He composed allegorical interpretations of the Bible and sacred poetry. His hymns were important in the early development of that form. Feast: Jan. 14; in England, Jan. 13 (Hilarymas). Hilary term, in English courts and schools, begins Jan. 11.

Diane de Poitiers, 1499-1566, duchess of Valentinois, mistress of King Henry II of France. Noted for her beauty, Diane, who was much older than Henry, retained her influence over him until his death (1559). She maintained friendly relations with the queen, Catherine de' Medici, while completely eclipsing her. In the rivalry for Henry's favor between Anne, duc de Montmorency, and the Guise family, she took sides against whichever party was more powerful at the moment. She supported the king's anti-Protestant policy. After Henry's death, she was forced to retire from the court.