midnight
The prince placed himself at their head , but the magistrates and burghers of the towns would not allow him to hazard a life so indispensable to the existence of Holland , and the troops themselves refused to march unless he abandoned his intention . He at last reluctantly consented , and handed over the command of the expedition to Baron Batenburg . On the 8th of July at dusk the expedition set out from Sassenheim , taking with them four hundred wagon loads of provisions and seven cannon . They halted in the woods , and remained till midnight . Then they again marched forward , hoping to be able to surprise the Spaniards and make their way through before these could assemble in force . The agreement had been made that signal fires should be lighted , and that the citizens should sally out to assist the relieving force as it approached . Unfortunately two pigeons with letters giving the details of the intended expedition had been shot while passing over the Spanish camp , and the besiegers were perfectly aware of what was going to be done .