The religious revolution of the Reformation erupted in violent riots in August 1566, as in other parts of the Low Countries. The regent Margaret, Duchess of Parma, was swept aside when Philip II sent the Duke of Alba at the head of an army the following summer. When the Eighty Years' War broke out in 1568, commercial trading between Antwerp and the Spanish port of Bilbao collapsed and became impossible. On 4 November 1576, Spanish soldiers sacked the city during the so-called Spanish Fury: 7,000 citizens were massacred, 800 houses were burnt down, and over £2 million sterling of damage was done.