receive a fatal blow.

In the mean time Gisilbrecht, the youthful Duke of Lotharingia, again
rebelled, but was besieged and taken prisoner in Zuelpich by Henry, who,
struck by his noble appearance, restored to him his dukedom, and
bestowed upon him his daughter, Gerberga, in marriage. Rudolph of France
also sued for peace, being hard pressed by his powerful rival, Hugo the
Great or Wise, the son of Robert. Charles the Simple was, on Henry's
demand, restored to liberty, but quickly fell anew into the power of his
faithless vassals.

Peace was now established throughout the empire, and afforded Henry an
opportunity for turning his attention to the introduction of measures,
in the interior economy of the State, calculated to obviate for the
future the dangers that had hitherto threatened it from without. The
best expedient against the irruptions of the Hungarians appeared to him
to be the circumvallation of the most important districts, the erection
of forts and of fortified cities. The most important point, however, was
to place the garrisons immediately under him as citizens of the State,
commanded by his immediate officers, instead of their being indirectly
governed by the feudal aristocracy and by the clergy. As these garrisons
were intended not only for the protection of the walls, but also for
open warfare, he had them trained to fight in rank and file, and formed
them into a body of infantry, whose solid masses were calculated to
withstand the furious onset of the Hungarian horse. These garrisons were
solely composed of the ancient freemen, and the whole measure was, in
fact, merely a reform of the ancient _arrier-ban_, which no longer
sufficed for the protection of the State, and whose deficiency had long
been supplied by the addition of vassals under the command of their
temporal or spiritual lieges, and by the mercenaries or bodyguards of
the emperors. The ancient class of freemen, who originally composed the
arrier-ban, had been gradually converted into feudal vassals; but they
were at that time still so numerous as to enable Henry to give them a
completely new military organization, which at once secured to them
their freedom, hitherto endangered by the preponderating power of the
feudal aristocracy, and rendered them a powerful support to the throne.
By collecting them into the cities, he afforded them a secure retreat
against the attempts of the grafs, dukes, abbots, and bishops, and
created for himself a b