Eighty Years' War (1566–1609)

The first half of the Eighty Years' War between the Spanish Empire and the Dutch Republic was fought between 1566 and 1609. When the Twelve Years' Truce was signed in 1609, ending this stage of the war, the northern Netherlands had achieved de facto independence.

Calvinist protest against the wealth of the church led to the iconoclastic fury (Dutch: Beeldenstorm) across the Netherlands. The Governor of the Netherlands Margaret of Parma, as well as authorities at lower levels, feared insurrection and made further concessions to the Calvinists, such as designating certain churches for Calvinist worship. Some provincial governors, foremost Philip of Noircarmes of Hainaut, who suppressed the revolt of the Calvinists led by Guido de Bres in Valenciennes, and William of Orange as stadtholder of Holland and Zeeland, took decisive action to quell the disturbances.

In March 1567 at the Battle of Oosterweel Calvinists under John of St. Aldegonde were defeated by a royalist army and all rebels summarily executed. In April 1567, Margaret reported to her brother Philip II that order had been restored. However, by the time this news reached him in Madrid, the Duke of Alba had already been dispatched with an army to restore order. Rather than working with Margaret, Alba took over command and Margaret resigned in protest.

Alba established the Council of Troubles (soon to be nicknamed the Blood Council) on 5 September 1567, which conducted a campaign of repression of suspected heretics and people deemed guilty of the already extinguished insurrection. Many high-ranking officials were arrested on various pretexts, among them the Counts of Egmont and Horne who were executed for treason on 5 June 1568 while attesting to their Catholic orthodoxy on the scaffold. Of the 9,000 accused, about 1,000 were executed, and many fled into exile, including William of Orange.

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