WILLIAM THE CONQUEROR 95 Northumbria, exhausted and ruined, gave up the struggle, and the omission of the northern counties from the Domesday survey throws a grim light on the completeness of the Conquest. In one district only, the fens of Cambridgeshire, where Hereward still held out, the spirit of resistance survived. In April, 1071, William arrived at Cambridge and commenced a regular blockade. Advancing cautiously by means of a causeway through the fens, he entered Ely in October, and therewith the last flicker of independence died out. The conquest of Eng- land was completed. To guard against any fresh incitements to rebellion from Scotland, William in 1072 invaded that country and forced Malcolm to do him homage an event which had an important effect on the subsequent relations of the two countries. Henceforward such trouble as William met with came, not from the English, but from his Norman vassals or his own family. In 1073 the citizens of Le Mans took advantage of his absence to set up a "commune," and invited Fulk oi Anjou to protect them. William was soon in the field, this time assisted by English troops. He harried the country, recovered Le Mans, and made an ad- vantageous peace with the count. By a skilful compromise he recognized Fulk as qyerlord of Maine, but kept actual possession of the district, for which his son Robert did homage. A year later a formidable revolt broke out in England. Two of William's great vassals, Ralph, Earl of Norfolk, and Roger, Earl of Here- ford, rebelled, and a Danish fleet, probably in alliance with them, appeared in the Humber. William returned at once to England and put down the insurrection. A great meeting of the witan vvas summoned to try Roger and Waltheof, for the latter, though he took no part in the rebellion, had undoubtedly been privy to it. Roger was imprisoned for life and Waltheof was condemned to death. This was the last instance of opposition to William in England ; but the remaining ten years of his life were occupied with almost continuous troubles on the Continent. In 1076 he was engaged in a war with Brittany, which the inter- ference of Philip of France forced him to bring to an unsuccessful conclusion. Next year he quarrelled with his son Robert. Matilda took the young man's side against her husband, and Philip lent him his assistance. In 1080 William was at open war with his son. While besieging him at Gerberoi he received a wound and was forced to raise the siege. A temporary reconciliation followed, soon to give way to another and a final quarrel. Three years later Matilda died, and troubles thickened upon William. A rebellious vassal, Hubert of Beaumont, seems to have held him at bay for nearly three years. Rival claims to Vexin, a district on the eastern frontier of Normandy, involved him in another war with France. He was growing old and weary, and, as he lay sick at Rouen in the summer of 1087, the French army harried his territories with impunity. When he had recovered sufficiently to take the field, he invaded Vexin and burned the town of Mantes. But his horse, plunging in the burning cinders, inflicted on him an internal injury, which proved his death-wound He was carried to St. Gervais, where, on September 9, 1087, he died. His body was conveyed to Caen and buried in the great minster which he had built.