The atmosphere in the Netherlands was tense due to the rebellion preaching of Calvinist leaders, hunger after the bad harvest of 1565, and economic difficulties due to the Northern Seven Years' War. Early August 1566, a mob stormed the church of Hondschoote in Flanders (now in Northern France). This relatively small incident spread North and led to a massive iconoclastic movement by Calvinists, who stormed churches and other religious buildings to desecrate and destroy statues and images of Catholic saints all over the Netherlands.

According to the Calvinists, these statues represented worship of idols. The number of actual image-breakers appears to have been relatively small and the exact backgrounds of the movement are debated, but in general, local authorities did not step in to rein in the vandalism.

The actions of the iconoclasts drove the nobility into two camps, with Orange and other grandees opposing the movement and others, notably Henry of Brederode, supporting it. Even before he answered the petition by the nobles, Philip had lost control in the troublesome Netherlands. He saw no other option than to send an army to suppress the rebellion. On 22 August 1567, Fernando Álvarez de Toledo, 3rd Duke of Alba, marched into Brussels at the head of 10,000 troops

Bron: Wikipedia (Engels)