It is generally believed that the system of feudal tenures was legally established in England at the Council of Salisbury, held either in 1085 or 1086. The great characteristic of the feudal system was that the obligation of military or knight's service was annexed to the tenure of land held of the sovereign. The estates, or fiefs of the tenants-in-chief, consisted of one or more knight's fees; and for every fee the king might claim the military service of an armed knight for forty days a year. The holders of these estates, on taking possession, were required to do homage, and to swear fealty to the king; and on particular and specified occasions other services were exacted. The holders of large estates often granted portions of their land to under-vassals, from whom they received services similar to those which they themselves rendered to their sovereign. The number of knight's fees in England was 60,215. About this time _the ecclesiastical was separated from the civil jurisdiction_; all causes of the Church were to be tried before clerical tribunals. 1086. =Domesday Book completed.= This invaluable record, the result of a survey begun about the year 1080, consists of two volumes, and contains an account of the extent and value of the landed property of the country, together with many other important particulars. 1087. William engaged in war with Philip I. of France. He was seriously hurt at Mantes, and the injury terminated fatally. In this reign the mode of _trial by combat_ began to be employed. The curfew-bell was tolled every night at eight o'clock, at which time all fires were to be put out. WILLIAM II., surnamed RUFUS. =D.= He was the son of William I. =B.= about 1060. =Killed= in the New Forest, Aug. 2, 1100, =R.= 13 years (1087 to 1100). 1088. Several of the principal Norman nobles conspired against the king. The insurrection suppressed by the aid of the Saxons. 1090. William intrigued against his elder brother Robert, duke of Normandy, in the hope of acquiring the duchy. 1091. William invaded Normandy. A treaty concluded between the brothers, by which the king obtained several towns in the duchy. Malcolm III., king of Scotland, invaded England, but was repulsed. 1093. Malcolm invaded England, and was slain at ALNWICK. 1095. =Urban II. preached the first Crusade at Clermont in Auvergne=, and induced several of the princes of Europe to take part in the enterprise. The object of the Crusades was to recover Jerusalem and the Holy Land from the Turks, who treated the Christian pilgrims with great harshness and cruelty. These wars lasted about 174 years, and exercised great political influence on the Continent. The only Crusade in which the English played an important part was that undertaken by Richard I. 1096. Robert mortgaged his duchy to William, in order that he might join the Crusade.