Fernando Álvarez de Toledo, the third Duke of Alba was a Spanish general and governor of the Spanish Netherlands (1567 - 1573), nicknamed "the Iron Duke" by Protestants of the Low Countries because of harsh rule. Although the Duke led oppressive and brutal military operations in Flanders, his cruelty was exaggerated in Dutch and English folklore, forming a new and central component of the Black Legend.
In 1567, Philip, who was a zealous prosecutor of Protestants, sent Alba into the Netherlands at the head of an army of 10,000 men, with unlimited powers for the extirpation of heretics. When he arrived he soon showed how much he merited the confidence which his master reposed in him, and instantly erected a tribunal which soon became known to its victims as the "Blood Council," to try all persons who had been engaged in the late commotions which the civil and religious tyranny of Philip had excited. During the six years of his governorship, no less than 18,000 people were executed. He imprisoned the counts Egmont and Hoorn, the two popular leaders of the dissatisfied Dutch nobles, and had them condemned to death even though they were opposed to the Protestants.