The last letter that the governor despatched said that longer resistance was impossible. The garrison were reduced to a mere remnant, and these utterly worn out by constant fighting and the want of rest. He should ask for fair and honourable terms, but if these were refused the garrison and the whole male inhabitants in the city, putting the women and children in the centre, would sally out and cut their way through, or die fighting in the midst of the Spaniards. The swimmer who took the letter was drowned, but his body was washed ashore and the letter taken to the Duke of Parma.
Three days afterwards a fresh force of the enemy embarked in forty large boats, and were about to land on an unprotected wharf by the riverside when Arnold de Groenvelt hung out the white flag. His powder was exhausted and his guns disabled, and the garrison so reduced that the greater portion of the walls were left wholly undefended. The Duke of Parma, who was full of admiration at the extraordinary gallantry of the defenders, and was doubtless also influenced by the resolution expressed in his letter by the governor, granted them most honourable terms. The garrison were to march out with all their baggage and arms, with matches lighted and colours displayed. They were to proceed to Breskans, and there to embark for Flushing. The life and property of the inhabitants were to be respected, and all who did not choose to embrace the Catholic faith were to be allowed to leave the town peaceably, taking with them their belongings, and to go wheresoever they pleased.
When the gates were opened the garrison sallied out. The Duke of Parma had an interview with several of the leaders, and expressed his high admiration of the valour with which they had fought, and said that the siege of Sluys had cost him more men than he had lost in the four principal sieges he had undertaken in the Low Country put together. On the 4th of August the duke entered Sluys in triumph, and at once began to make preparations to take part in the great invasion of England for which Spain was preparing.
After their arrival at Flushing Captains Vere, Uvedale, and others, who had brought their companies from Bergen op Zoom to aid in the defence of Sluys, returned to that town.
The Earl of Leicester shortly afterwards resigned his appointment as general of the army. He had got on but badly with the States General, and there was from the first no cordial cooperation between the two armies. The force at his disposal was never strong enough to do anything against the vastly superior armies of the Duke of Parma, who was one of the most brilliant generals of his age, while he was hampered and thwarted by the intrigues and duplicity of Elizabeth, who was constantly engaged in half hearted negotiations now with France and now with Spain, and whose capricious temper was continually overthrowing the best laid plans of her councillors and paralysing the actions of her commanders. It was not until she saw her kingdom threatened by invasion that she placed herself fairly at the head of the national movement, and inspired her subjects with her energy and determination.