Fernando Álvarez de Toledo, 3rd Duke of Alba was sent by Philip II of Spain to Belgium where he waged war against the protestants in the area.
As a bit of history, Belgium in the 16th Century started out as part of the "Seventeen Provinces" within the Burgundian Netherlands. Belgium was formed after the Eighty Years' War (1568–1648)
On February 16, 1568, the entire population of the Netherlands—three million—was condemned to death as heretics, apart from a few named exceptions:
Philip next submitted a "Memorial and Representation" of the state of the Low Countries to the Spanish Inquisition craving the judgment of the Fathers upon it. After deliberating, the inquisitors pronounced their decision on the 16th of February, 1568. It was to the effect that, "with the exception of a select list of names which had been handed to them, all the inhabitants of the Netherlands were heretics or abettors of heresy, and so had been guilty of the crime of high treason." On the 26th of the same month, Philip confirmed this sentence by a proclamation, in which he commanded the decree to be carried into immediate execution, without favour or respect of persons. The King of Spain actually passed sentence of death upon a whole nation. We behold him erecting a common scaffold for its execution, and digging one vast grave for all the men, and women, and children of the Low Countries. "Since the beginning of the world," says Brandt, "men have not seen or heard any parallel to this horrible sentence. (Wylie, History of Protestantism, vol. II, p. 70.)
Would the sending of the 3rd Duke of Alba to Belgium and his following actions be considered a Catholic Crusade?