William Longsword, 3rd earl of Salisbury (died March 7, 1226, Salisbury, Wiltshire, England) was the 3rd earl of Salisbury, an illegitimate son of Henry II of England who became a prominent baron, soldier, and administrator under Kings John and Henry III. His parentage was, for many centuries, a mystery. He was long assumed to have been the son of Rosamond, with whom Henry II had an infamous affair. By the early 21st century, however, documents had been discovered that indicated that his mother was probably Countess Ida de Tosny, who later married Roger Bigod, 2nd earl of Norfolk.
Longsword was recognized as a son by Henry II and granted use of the coat of arms of his grandfather, Geoffrey IV. Henry also granted Longsword the honour of Appleby, in Lincolnshire, in 1188. In 1196 Richard I gave him the hand of Ela (or Isabel), daughter and heir of William Fitzpatrick, earl of Salisbury, thus making Longsword the earl of Salisbury. Among the many official positions to which Salisbury was appointed were the sheriff of Wiltshire (1199–1202, 1203–07, 1213–26), lieutenant of Gascony (1202), warden of the Cinque Ports (1204–06), honour of Eye (1205), warden of the Welsh Marches (1208), and sheriff of Cambridgeshire and Huntingdonshire (1212–16).
He was sent on missions to France (1202) and to Germany (1209). In 1213–14 he organized John’s Flemish allies, taking part in the destruction (1213) of the French fleet at Damme, then the port of Bruges, and leading the right wing of the allied army at Bouvines (July 27, 1214), where he was captured by the bishop of Beauvais and held prisoner along with Ferrand, count of Flanders. Salisbury was exchanged for Robert of Dreux and was back in England by May 1215, when he was employed by John in inspecting the defenses of royal castles and fighting the rebels in the southwest.
During John’s war against the barons, Salisbury deserted the king after the landing of Louis VIII of France (May 1216). He returned to royal allegiance, however, by March 1217, fought at Lincoln (May) and Sandwich (August), and attested the Treaty of Lambeth (September 1217). Salisbury held various posts during the minority of Henry III and served against the Welsh in 1223 and in Gascony in 1225. He and his wife were benefactors of Salisbury Cathedral and laid foundation stones of the new cathedral in 1220. He was buried there and his effigy, a splendid early example, still survives. It is popularly believed that Salisbury was poisoned by Hubert de Burgh, but there is little evidence aside from Roger of Wendover’s account in Flores historiarum.
Since his death, Salisbury has become a recurring character in legend and literature. He was generally regarded in a positive light by the chroniclers of the era, and the relative lack of information about him seems to have made him a figure of speculation for antiquarians and romantics. One of Salisbury’s earliest appearances in literature was in William Shakespeare’s “The Life and Death of King John,” in which he appears as a minor character, a conciliatory voice between John and his frustrated barons. He became a protagonist in his own right with the publication of Thomas Leland’s Longsword, Earl of Salisbury (1762), which draws heavily on Roger of Wendover’s account of Salisbury’s life and death. In the 21st century Salisbury appeared as a central character in Elizabeth Chadwick’s historical romance To Defy a King (2010) and Cornelia Funke’s children’s novel Ghost Knight (2012).