The Army of Flanders was to play a key part in all the campaigns of the Dutch Revolt (1567–1609). The Duke of Alba had first brought the army into Flanders, and despite losing the Battle of Heiligerlee to William I of Orange, the rebel leader, was able to pacify the north until a resurgence of rebel activity occurred in 1572. Alba sent his son Fadrique to quell the insurrection with some 30,000 men, Spaniards, Walloons, and Germans. The Army of Flanders crushed the weak defenses of Zutphen and put nearly every man in town to death, hanging some by the feet while drowning 500 others. At Naarden the women were publicly raped, then every living thing was put to the sword. The Army of Flanders now pushed through Amsterdam and, basing there, advanced against Haarlem at the beginning of December 1572. Haarlem had a garrison of some 4,000 troops led by Wigbolt Ripperda. The citizens would fight resolutely alongside the soldiers. For weeks on end, the Spanish guns pounded the city defences but to no avail; they also tried tunnelling towards the city walls to mine the remaining defences but the Dutch dug counter-tunnels and blew up any Spanish and their tunnels they might meet. From the outside, William of Orange made use of the winter freeze to smuggle in provisions over the frozen Haarlem Lake on sledges. This was done under the very noses of the shocked Spanish, who had never seen skating. Even after the freeze, in early 1573, William's Sea Beggars maintained the supply line by boat under the cover of a thick mist which hung over the lake. The Dutch made frequent sorties, cut off the heads of the soldiers they captured and rolled them into the Spanish lines in barrels; the Spaniards hanged their prisoners on crosses facing the enemy; and the Dutch defenders taunted the Spanish besiegers by staging parodies of Catholic rituals on the cities ramparts.