Eighty Years' War, 1566–1572

The period between the start of the Beeldenstorm in August 1566 until early 1572 (before the Capture of Brielle on 1 April 1572) contained the first events of a series that would later be known as the Eighty Years' War between the Spanish Empire and disparate groups of rebels in the Habsburg Netherlands. Some of the first pitched battles and sieges between radical Calvinists and Habsburg governmental forces took place in the years 1566–1567, followed by the arrival and government takeover by Fernando Álvarez de Toledo, 3rd Duke of Alba (simply known as "Alba" or "Alva") with an army of 10,000 Spanish and Italian soldiers. Next, an ill-fated invasion by the most powerful nobleman of the Low Countries, the exiled but still-Catholic William "the Silent" of Orange, failed to inspire a general anti-government revolt. Although the war seemed over before it got underway, in the years 1569–1571, Alba's repression grew severe, and opposition against his regime mounted to new heights and became susceptible to rebellion.

Although virtually all historians place the start of the war somewhere in this period, there is no historical consensus on which exact event should be considered to have begun the war. Consequently, there is no agreement whether the war really lasted exactly eighty years. For this and other reasons, some historians have endeavoured to replace the name "Eighty Years' War" with "Dutch Revolt", but there is also no consensus either to which period the term "Dutch Revolt" should apply (be it the prelude to the war, the initial stage(s) of the war, or the entire war).