The commander of the Spaniards now gave the order for a retreat. As they fell back the guns of the ships swept their ranks, the musketeers harassed them on each flank, the ice, cracked and broken by the artillery fire, gave way under their feet, and many fell through and were drowned, and of the thousand men who left Amsterdam less than half regained that city. The Spaniards were astonished at this novel mode of fighting, and the despatches of their officers gave elaborate descriptions of the strange appendages that had enabled the Hollanders to glide so rapidly over the ice. The Spaniards were, however, always ready to learn from a foe. Alva immediately ordered eight thousand pairs of skates, and the soldiers were kept hard at work practicing until they were able to make their way with fair rapidity over the ice. The evening after the fight a strong wind suddenly sprang up from the southwest, and the rain descended in torrents. By morning the ice was already broken up, the guns were hastily shifted to the vessels to which they belonged, the ships on the outside tiers cast off from the others, and before noon the whole were on their way back towards Enkhuizen, which they reached without pursuit by the Spanish vessels; for at nine in the morning the wind changed suddenly again, the frost set in as severely as before, and the Spaniards in the port of Amsterdam were unable to get out. This event caused great rejoicing in Holland, and was regarded as a happy omen for the coming contest. After remaining another day with his family, Ned mounted his horse and rode to Haarlem. The city lay at the narrowest point of the narrow strip of land facing the German Ocean, and upon the shore of the shallow lake of the same name. Upon the opposite side of this lake, ten miles distant, stood the town of Amsterdam. The Lake of Haarlem was separated from the long inlet of the Zuider Zee called the Y by a narrow strip of land, along which ran the causeway connecting the two cities. Halfway along this neck of land there was a cut, with sluice works, by which the surrounding country could be inundated. The port of Haarlem on the Y was at the village of Sparendam, where there was a fort for the protection of the shipping. Haarlem was one of the largest cities of the Netherlands; but it was also one of the weakest. The walls were old, and had never been formidable. The extent of the defences made a large garrison necessary; but the force available for the defence was small indeed. Upon his way towards Haarlem Ned learnt that on the night before, the 10th of December, Sparendam had been captured by the Spaniards. A secret passage across the flooded and frozen meadows had been shown to them by a peasant, and they had stormed the fort, killed three hundred men, and taken possession of the works and village. Thus Haarlem was at once cut off from all aid coming from the Zuider Zee.