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 Crèvecceur 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.
While all this was going on the Prince of Orange had been pushing forward the siege operations. On July 17 the forts of St Isabella and St Anthony were stormed. The attack against the main defences, in which the English regiments specially distinguished themselves, was now pressed with redoubled vigour. The resistance at every step was desperate, but at last the moat was[pg.145] crossed and a lodgment effected within the walls. On September 14 Hertogenbosch surrendered; and the virgin fortress henceforth became the bulwark of the United Provinces against Spanish attack on this side. The consummate engineering skill, with which the investment had been carried out, attracted the attention of all Europe to this famous siege. It was a signal triumph and added greatly to the stadholder's popularity and influence in the republic.
It was needed. The Estates of Holland were at this time once more refractory. The interests of this great commercial and maritime province differed from those of the other provinces of the Union; and it bore a financial burden greater than that of all the others put together. The Estates, then under the leadership of Adrian Pauw, the influential pensionary of Amsterdam, declined to raise the quota of taxation assigned to the province for military needs and proceeded to disband a number of troops that were in their pay. Inconsistently with this action they declined to consider certain proposals for peace put forward by the Infanta Isabel, for they would yield nothing on the questions of liberty of worship or of freedom to trade in the Indies. Their neglect to furnish the requisite supplies for the war, however, prevented the prince from undertaking any serious military operations in 1630. Fortunately the other side were in no better case financially, while the death of Spinola and the withdrawal of the Count de Berg from the Spanish service deprived them of their only two competent generals. This attitude of Holland, though it thwarted the stadholder's plans and was maintained in opposition to his wishes, by no means however implied any distrust of him or lack of confidence in his leadership. This was conclusively proved by the passing, at the instigation of Holland, of the Acte de Survivance (April 19,1631). This Act declared all the various offices held by the prince hereditary in the person of his five-year-old son. He thus became, in all but name, a constitutional sovereign.
An expedition planned for the capture of Dunkirk at this time, spring 1631, proved too hazardous and was abandoned, but later in the year the Dutch sailors gave a signal proof of their superiority at sea. Encouraged by the failure of the attempted attack on Dunkirk the government at Brussels determined on a counter-stroke. A flotilla of 35 frigates, accompanied by a large number of smaller vessels to carry supplies and munitions and having on board a body of 6000 soldiers, set sail from Antwerp under the command of[pg.146]Count John of Nassau (a cousin of the stadholder) and in the presence of Isabel herself to effect the conquest of some of the Zeeland islands. As soon as the news reached Frederick Henry, detachments of troops were at once despatched to various points; and about a dozen vessels were rapidly equipped and ordered to follow the enemy and if possible bring him to action. A landing at Terscholen was foiled by Colonel Morgan, who, at the head of 2000 English troops, waded across a shallow estuary in time to prevent a descent. At last (September 12) the Dutch ships managed to come up with their adversaries in the Slaak near the island of Tholen. They at once attacked and though so inferior in numbers gained a complete victory. Count John of Nassau just contrived to escape, but his fleet was destroyed and 5000 prisoners were taken.
The year 1632 witnessed a renewal of military activity and was memorable for the famous siege and capture of Maestricht. This fortress held the same commanding position on the eastern frontier as Hertogenbosch on the southern; and, though its natural position was not so strong as the capital of North Brabant, Maestricht, lying as it did on both sides of the broad Meuse, and being strongly fortified and garrisoned, was very difficult to invest. The stadholder, at the head of a force of 17,000 infantry and 4000 horse, first made himself master of Venloo and Roeremonde and then advanced upon Maestricht. Unfortunately before Roeremonde, Ernest Casimir, the brave stadholder of Friesland and Groningen, was killed. He was succeeded in his offices by his son, Henry Casimir. Arriving (June 10) before Maestricht, Frederick Henry proceeded to erect strongly entrenched lines of circumvallation round the town connecting them above and below the town by bridges. Supplies reached him plentifully by the river. To the English and French regiments were once more assigned the place of honour in the attack. All went well until July 2, when Don Gonzales de Cordova led a superior Spanish force from Germany, consisting of 18,000 foot and 6000 horse, to raise the siege, and encamped close to the Dutch lines on the south side of the river. Finding however no vulnerable spot, he awaited the arrival at the beginning of August of an Imperialist army of 12,000 foot and 4000 horse, under the renowned Pappenheim. This impetuous leader determined upon an assault, and the Dutch entrenchments were attacked suddenly with great vigour at a moment when the prince was laid up with[pg.147] the gout. He rose, however, from his bed, personally visited all the points of danger, and after desperate fighting the assailants were at last driven off with heavy loss. The Spaniards and Imperialists, finding that the stadholder's lines could not be forced, instituted a blockade, so that the besiegers were themselves besieged. But Frederick Henry had laid up such ample stores of munitions and provisions that he paid no heed to the cutting of his communications, and pushed on his approaches with the utmost rapidity. All difficulties were overcome by the engineering skill of the scientific commander; and finally two tunnels sixty feet deep were driven under the broad dry moat before the town walls. The English regiments during these operations bore the brunt of the fighting and lost heavily, Colonels Harwood and the Earl of Oxford being killed and Colonel Morgan dangerously wounded. After exploding a mine, a forlorn hope of fifty English troops rushed out from one of the tunnels and made good their footing upon the ramparts. Others followed, and the garrison, fearing that further resistance might entail the sacking of the town, surrendered (August 23) with honours of war.
One result of the fall of Maestricht was a renewal on the part of the Archduchess Isabel of negotiations for peace or a long truce. On the authority of Frederick Henry's memoirs the terms first offered to him in camp were favourable and might have been accepted. When, however, the discussion was shifted to the Hague, the attitude of the Belgic representatives had stiffened. The cause was not far to seek, for on November 6, 1632 the ever-victorious Gustavus Adolphus had fallen in the hour of triumph in the fatal battle of Lützen. The death of the Swedish hero was a great blow to the Protestant cause and gave fresh heart to the despondent Catholic alliance. The negotiations dragged however their slow length along, the chief point of controversy being the old dispute about freedom to trade in the Indies. On this point agreement was impossible. Spain would yield nothing of her pretensions; and the Hollanders would hear of no concessions that threatened the prosperity of the East and West India Companies in which so many merchants and investors were deeply interested. Any admission of a Spanish monopoly or right of exclusion would have spelt ruin to thousands. The diplomatic discussions, however, went on for many months in a desultory and somewhat futile manner; and meanwhile[pg.148] though hostilities did not actually cease, the campaign of 1633 was conducted in a half-hearted fashion. The death of Isabel on November 29, 1633, shattered finally any hopes that the peace party in the Provinces (for there was a strong peace party) might have had of arriving at any satisfactory agreement. By the decease of the arch-duchess, who had been a wise and beneficent ruler and had commanded the respect and regard not only of her own subjects but of many northerners also, the Belgic provinces reverted to the crown of Spain and passed under the direct rule of Philip IV. The Cardinal Infante Ferdinand, fresh from his crushing victory over the Swedes at Nördlingen, came as governor to Brussels in 1634, at the head of considerable Spanish forces, and an active renewal of the war in 1635 was clearly imminent.
In these circumstances Frederick Henry determined to enter into negotiations with France for the conclusion of an offensive and defensive alliance against Spain, the common enemy. He had many difficulties to encounter. The Estates of Holland, though opposed to the terms actually offered by the Brussels government, were also averse to taking any step which shut the door upon hopes of peace. Richelieu on his side, though ready, as before, to grant subsidies and to permit the enrolment of French regiments for the Dutch service, shrank from committing France to an open espousal of the Protestant side against the Catholic powers. The stadholder, however, was not deterred by the obstacles in his way; and the diplomatic skill and adroitness of Aerssens, aided by his own tact and firmness of will, overcame the scruples of Richelieu. The opposition of the Estates of Holland, without whose consent no treaty could be ratified, was likewise surmounted. Adrian Pauw, their leader, was despatched on a special embassy to Paris, and in his absence his influence was undermined, and Jacob Cats was appointed Council-Pensionary in his stead. In the spring of 1635 a firm alliance was concluded between France and the United Provinces, by which it was agreed that neither power should make peace without the consent of the other, each meanwhile maintaining a field force of 25,000 foot and 5000 horse and dividing conquests in the Southern Netherlands between them. This treaty was made with the concurrence and strong approval of the Swedish Chancellor, Oxenstierna, and was probably decisive in its effect upon the final issue of the Thirty Years' War.[pg.149]
In the early spring of 1635, therefore, a French force entered the Netherlands and, after defeating Prince Thomas of Savoy at Namur, joined the Dutch army at Maestricht. Louis XIII had given instructions to the French commanders, Châtillon and de Brézé, to place themselves under the orders of the Prince of Orange; and Frederick Henry at the head of 32,000 foot and 9000 horse now entered the enemy's territory and advanced to the neighbourhood of Louvain. Here however, owing to the outbreak of disease among his troops, to lack of supplies and to differences of opinion with his French colleagues, the prince determined to retreat. His action was attended by serious results. His adversary, the Cardinal Infante Ferdinand, was a wary and skilful general. He now seized his opportunity, rapidly made himself master of Diest, Gennep, Goch and Limburg, and took by surprise the important fort of Schenck at the junction of the Waal and the Rhine. Vexed at the loss of a stronghold which guarded two of the main waterways of the land, the stadholder at once laid siege to Schenck. But the Spanish garrison held out obstinately all through the winter and did not surrender until April 26,1636. The Dutch army had suffered much from exposure and sickness during this long investment and was compelled to abstain for some months from active operations. Ferdinand thereupon, as soon as he saw that there was no immediate danger of an attack from the north, resolved to avenge himself upon the French for the part they had taken in the preceding year's campaign. Reinforced by a body of Imperialist troops under Piccolomini he entered France and laid the country waste almost to the gates of Paris. This bold stroke completely frustrated any plans that the allies may have formed for combined action in the late summer.
The following year the States determined, somewhat against the wishes of Frederick Henry, to send an expedition into Flanders for the capture of Dunkirk. This was done at the instance of the French ambassador, Charnacé, acting on the instructions of Richelieu, who promised the assistance of 5000 French troops and undertook, should the town be taken, to leave it in the possession of the Dutch. The stadholder accordingly assembled (May 7) an army of 14,000 foot and a considerable body of horse at Rammekens, where a fleet lay ready for their transport to Flanders. Contrary winds, however, continued steadily to blow for many weeks without affording any opportunity for putting to sea. At last, wearied out with the long[pg.150] inaction and its attendant sickness the prince (July 20) suddenly broke up his camp and marched upon Breda. Spinola, after capturing Breda in 1625, had greatly strengthened its defences; and now, with a garrison of 4000 men under a resolute commander, it was held to be secure against any attack. The siege was a repetition of those of Hertogenbosch and Maestricht. In vain did the Cardinal Infante with a powerful force try to break through the lines of circumvallation, which the prince had constructed with his usual skill. Called away by a French invasion on the south, he had to leave Breda to its fate. The town surrendered on October 10.
During the years 1637 and 1638 the ever-recurring dissensions between the province of Holland and the Generality became acute once more. The Provincial Estates insisted on their sovereign rights and refused to acknowledge the authority of the States-General to impose taxes upon them. This opposition of Holland was a great hindrance to the prince in the conduct of the war, and caused him constant anxiety and worry. It was impossible to plan or to carry out a campaign without adequate provision being made for the payment and maintenance of the military and naval forces, and this depended upon Holland's contribution. Amsterdam was the chief offender. On one occasion a deputation sent to Amsterdam from the States-General was simply flouted. The burgomaster refused to summon the council together, and the members of the deputation had to return without an audience. All the prince's efforts to induce the contumacious city to consider his proposals in a reasonable and patriotic spirit were of no avail; they were rejected insultingly. In his indignation Frederick Henry is reported to have exclaimed, "I have no greater enemy, but if only I could take Antwerp, it would bring them to their senses."