Excerpts from Books and Wikipedia
"The 1568 victory over a Spanish force at Heiligerlee in the Gronigen Province is regarded as the start of the Eighty Years' War, the long struggle for Dutch independence that would end in 1648 when the Spanish formally recognized the Dutch Republic at the Peace of Westphalia. . . . When, in 1566, in an outbreak of violence against the Catholic religion, mobs stormed churches and smashed statues, Philip II sent in an army of 10,000 troops under the duke of Alba to stem the rising tide of rebellion. Alba's brutal policies caused outrage." [Furtado: 1001 Days] "By the 1580s, what had earlier been a local rebellion by Dutch Protestants against Spanish rule had widened into a new international struggle." [Kennedy: Great Powers, p. 38]