orse--half-disciplined troops, partly Huguenot volunteers,
partly German mercenaries--he tried to cross the Meuse above Maestricht
with the intention of effecting a junction with the Prince of Orange.
He was accompanied by John and Henry of Nassau, his brothers, and
Christopher, son of the Elector Palatine. He found his course blocked
by a Spanish force under the command of Sancho d'Avila and Mondragon.
The encounter took place on the heath of Mook (April 14) and ended in
the crushing defeat of the invaders. Lewis and his young brother,
Henry, and Duke Christopher perished, and their army was completely
scattered. The death of his brothers was a great grief to William.
Lewis had for years been his chief support, and the loss of this
dauntless champion was indeed a heavy blow to the cause for which he
had sacrificed his life. He was only thirty-six years of age, while
Henry, the youngest of the Nassaus, to whom the Prince was deeply
attached, was but a youth of twenty-four.

The invasion of Lewis had nevertheless the result of raising the siege
of Leyden; but only for a time. After the victory at Mook the Spanish
troops were free to continue the task of reconquering rebel Holland for
the king. On May 26 a strong force under Valdez advanced to Leyden and
completely isolated the town by surrounding it with a girdle of forts.
The attack came suddenly, and unfortunately the place had not been
adequately provisioned. So strong was the position of the Spaniards that
the stadholder did not feel that any relieving force that he could send
would have any chance of breaking through the investing lines and
revictualling the garrison. In these circumstances he summoned, June 1,
a meeting of the Estates of Holland at Rotterdam and proposed, as a
desperate resource, that the dykes should be cut and the land submerged,
and that the light vessels of the Sea-Beggars under Boisot should sail
over the waters, attack the Spanish forts and force an entrance into the
town. After considerable opposition the proposal was agreed to and the
waters were allowed to flow out upon the low-lying fields, villages and
farms, which lie between the sea, the Rhine, the Waal and the Maas.
Unfortunately the season was not favourable, and though the water
reached nearly to the higher land round Leyden on which the Spanish
redoubts were erected, and by alarming Valdez caused him to press the
blockade more closely, it was not deep enough even for the light-draug