The Prince had indeed been doing all which, under the circumstances, was possible.  He assembled the citizens of Delft in the market-place, and announced his intention of marching in person to the relief of the city, in the face of the besieging army, if any troops could be obtained.  Soldiers there were none; but there was the deepest sympathy for Harlem throughout its sister cities, Delft, Rotterdam, Gouda.  A numerous mass of burghers, many of them persons of station, all people of respectability, volunteered to march to the rescue.  The Prince highly disapproved of this miscellaneous army, whose steadfastness he could not trust.  As a soldier, he knew that for such a momentous enterprise, enthusiasm could not supply the place of experience.  Nevertheless, as no regular troops could be had, and as the emergency allowed no delay, he drew up a commission, appointing Paulus Buys to be governor during his absence, and provisional stadholder, should he fall in the expedition.  Four thousand armed volunteers, with six hundred mounted troopers, under Carlo de Noot, had been assembled, and the Prince now placed himself at their head.  There was, however, a universal cry of remonstrance from the magistracies and burghers of all the towns, and from the troops themselves, at this project.  They would not consent that a life so precious, so indispensable to the existence of Holland, should be needlessly hazarded.  It was important to succor Harlem, but the Prince was of more value than many cities.  He at last reluctantly consented, therefore, to abandon the command of the expedition to Baron Batenburg, the less willingly from the want of confidence which he could not help feeling in the character of the forces.  On the 8th of July, at dusk, the expedition set forth from Sassenheim.  It numbered nearly five thousand men, who had with them four hundred wagon-loads of provisions and seven field-pieces.  Among the volunteers, Oldenbarneveld; afterwards so illustrious in the history of the Republic; marched in the ranks, with his musket on his shoulder.  Such was a sample of the spirit which pervaded the population of the province.

Batenburg came to a halt in the woods of Nordwyk, on the south aide of the city, where he remained till midnight.  All seemed still in the enemy’s camp.  After prayers, he gave orders to push forward, hoping to steal through the lines of his sleeping adversaries and accomplish the relief by surprise.  He was destined to be bitterly disappointed.  His plans and his numbers were thoroughly known to the Spaniards, two doves, bearing letters which contained the details of the intended expedition, having been shot and brought into Don Frederic’s camp.