Sir Roger de Leybourne (1215–1271) was an English soldier, landowner and royal servant during the Second Barons' War. Origins Roger was the younger son of another Sir Roger de Leybourne, by his first wife, Eleanor, the daughter and heiress of Stephen of Thornham. In 1199, when the elder Roger was still a minor, his wardship was sold to Thornham for 300 marks. The elder Roger then joined the rebels at the start of the First Barons' War in 1215, being captured in November at the siege of Rochester Castle, paying 250 marks for his release. After the death of the elder Roger some time before 1251 his son William de Leybourne inherited seven Knight's fees in Kent and Oxfordshire, as well as substantial debts, which were only cancelled in 1253 by Henry III. Life Roger first came to royal notice in 1252 when he killed Arnulf de Munteny, one of the king's household knights, in a jousting tournament with a sharpened lance, avenging himself of an injury caused by Arnulf in a previous tournament. To atone for his crime he "took the cross" (went on a Pilgrimage), and was pardoned by King Henry III. In 1253 he was given the lands of Roger Connell in Kent, and from then until his death he spent large amounts of time and money acquiring land in that county. In 1257 he served in the army of Lord Edward as part of his campaign in Wales, and became part of an influential group of his supporters. He joined Edward in autumn 1259 when he allied with Simon de Montfort, and was made custodian of Bristol Castle in November. He was part of Edward's retinue in 1260 when he and the Earl of Gloucester attempted to take London, and was one of those pardoned when Edward patched up his relationship with Henry III. In thanks for this service Edward gave him the manor of Elham in Kent, but in 1262 the grant was deemed to be in violation of the conditions of Henry giving the manor to Edward in the first place, and the manor was returned, with the High Sheriff of Kent being ordered to take £1,820 from Leybourne's lands; Leybourne frustrated him by simply removing all the goods from his lands in Kent, Essex and Sussex. In 1263 he along with other Marcher Lords arrested Peter of Aigueblanche, Bishop of Hereford, and seized