"We learn from a Saxon chronicle (A.D. 1085), that in the
nineteenth year of King William's reign, an invasion was
apprehended from Denmark; and the military constitution of the
Saxons being then laid aside, and no other introduced in its stead,
the kingdom was wholly defenceless; which occasioned the king to
bring over a large army of Normans and Britons who were quartered
upon, and greatly oppressed, the people. This apparent weakness,
together with the grievances occasioned by a foreign force, might
co-operate with the king's remonstrance, and better incline the
nobility to listen to his proposals for putting them in a position
of defence. For, as soon as the danger was over, the king held a
great council to inquire into the state of the nation, the
immediate consequence of which was the compiling of the great
survey called the Doomsday Book, which was finished the next year;
and in the end of that very year (1086) the king was attended by
all his nobility at Sarum, where the principal landholders
submitted their lands to the yoke of military tenure, and became
the king's vassals, and did homage and fealty to his person."

Mr. Henry Hallam writes:

"One innovation made by William upon the feudal law is very
deserving of attention. By the leading principle of feuds, an oath
of fealty was due from the vassal to the lord of whom he
immediately held the land, and no other. The King of France long
after this period had no feudal, and scarcely any royal, authority
over the tenants of his own vassals; but William received at
Salisbury, in 1085, the fealty of all landholders in England, both
those who held in chief and their tenants, thus breaking in upon
the feudal compact in its most essential attribute--the exclusive