rivers could feel reasonably secure against sudden attack.  It was with this object that in 1629 he determined to lay siege to the town of Hertogenbosch.  A force of 24,000 infantry and 4000 cavalry were gathered together for the enterprise.  It was composed of many nationalities, like all the armies commanded by Maurice and Frederick Henry, but was admirably disciplined and devoted to its commander.  Four English, three Scottish and four French regiments, all choice troops, raised by permission of their sovereigns for the service of the States, formed the backbone of the force.  On April 30 the town was invested.

Hertogenbosch, or Bois-le-duc, was strongly fortified, and so surrounded by marshy ground, intersected by a number of small streams, that the only way of approach for a besieging force was a single causeway defended by the forts of St Isabella and St Anthony.  The garrison consisted of 8000 men, and the governor, Grobendonc, was an experienced and resolute soldier.

The stadholder began by surrounding the town with a double line of circumvallation.  The marshes were crossed by dykes, and two streams were dammed so as to fill a broad deep moat round the lines and flood the country outside.  Other lines, three miles long, connected the investing lines with the village of Crevecceur on the Meuse, Frederick Henry’s base of supplies, which were brought by water from Holland.  These works completed, approaches were at once opened against the forts of St Anthony and St Isabella, the task being entrusted to the English and French troops.  The court of Brussels now began to take serious measures for relieving the town.  At first regarding Bolduc la pucelle as impregnable, they had been pleased to hear that the prince had committed himself to an enterprise certain to be a dismal failure.  Then came the news of the circumvallation, and with it alarm.  The Count de Berg was therefore ordered (June 17) at the head of an army of 30,000 foot and 7000 horse to advance into North Brabant and raise the siege.  But the stadholder was prepared and ceaselessly on his guard; and the Spanish general, after several vain attempts, found the Dutch lines unassailable.  With the view of compelling Frederick Henry to follow him, Berg now marched into the heart of the United Provinces, devastating as he went with fire and sword, took Amersfoort and threatened Amsterdam.  But the prince confined himself to despatching a small detached force of observation; and meanwhile a happy stroke, by which a certain Colonel Dieden surprised and captured the important frontier fortress of Wesel, forced the Spaniards to retreat, for Wesel was Berg’s depot of supplies and munitions.