e. 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 England 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 of 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 advantageous peace with the
count. By a skilful compromise he recognized Fulk as overlord 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 Hereford, 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
was 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 interference 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 wear