After the siege of the fortress of Mons (that had been captured by Louis of Nassau in May, 1572), Noircarmes was entrusted with the punishment of the citizens for their rebellion. Next he accompanied Alba to Mechelen and encouraged the Spanish soldiers to sack that city in October, 1572. Then he accompanied Alba's son Fadrique Álvarez de Toledo, 4th Duke of Alba on his punitive expedition to Holland. He took part in the Siege of Haarlem in 1573.