The summer of 1572 had been turbulent across the Low Countries. William of Orange, leading the Dutch revolt against Spanish Habsburg rule, had brought city after city under rebel control. Some embraced the cause enthusiastically; others, like Mechelen, simply opened their gates when rebel forces arrived. On August 31, Mechelen admitted William's troops, and the prince continued his advance toward Mons, leaving a garrison under Bernard van Merode. It was a strategic calculation that would prove catastrophic for the city. When William was forced to withdraw to Holland on September 21, Mechelen found itself exposed, a city that had tolerated rebels now facing the wrath of the most powerful military commander in Europe.

Fernando Alvarez de Toledo, the Duke of Alba, understood the power of terror. His unpaid troops were restless, and the rebellious cities of the south needed a demonstration of what defiance would cost. Mechelen was wealthy. Mechelen had harbored rebels. Mechelen would burn. Alba ordered his son, Fadrique Alvarez de Toledo, to punish the city. The plundering would serve two purposes: it would satisfy troops owed months of wages, and it would show every other city in Alba's path what awaited them. Bernard van Merode, learning of the approaching Spanish force, made a soldier's calculation and fled with his men. The citizens of Mechelen were left to face the consequences alone.

The sack began on October 2, 1572. Despite the city's peaceful surrender, despite the psalms and the open gates, Fadrique unleashed his soldiers for three days of systematic destruction. Protestant theologian Jean Leclerc, writing decades later, recorded accounts of slaughter, rape, and pillaging that stripped the city bare. Every house was entered. Every valuable taken. The violence was not spontaneous; it was policy. Alba's letter to Philip II expressed satisfaction that his message had been delivered. The Spanish Fury, as such episodes came to be known, was not the chaos of battle but the calculated deployment of terror as a political tool.

In the immediate aftermath, Alba's strategy succeeded. Every city in his path surrendered without resistance. Mechelen's suffering had purchased their obedience. Six weeks later, on November 15, Spanish troops repeated the performance at Zutphen. But terror, once unleashed, is difficult to control. Four years later, in 1576, unpaid Spanish soldiers would sack Antwerp without orders from any commander, killing thousands in what became the most infamous of the Spanish Furies. The distinction mattered: Mechelen and Zutphen were commanded atrocities; Antwerp was mutiny. Yet for the dead, for the survivors who watched their city burned, such distinctions meant nothing. The violence that served Alba's purposes in 1572 would ultimately help turn the entire Netherlands against Spanish rule.