These high-handed actions were the prelude to a reign of terror; and Margaret, already humiliated by finding herself superseded, requested her brother to accept her resignation.

On October 6 the office of Governor-General was conferred upon Alva; and shortly afterwards the duchess left the Netherlands and returned to Parma.
Alva had now the reins of power in his hand, and with a relentless zeal and cold-blooded ferocity, which have made his name a by-word, he set about the accomplishment of the fell task with which his master had entrusted him.

He had to enforce with drastic rigour all the penalties decreed by the placards against heretics and preachers, and to deal summarily with all who had taken any part in opposition to the government.

But to attempt to do this by means of the ordinary courts and magistrates would consume time and lead to many acquittals.

Alva therefore had no sooner thrown off the mask by the sudden and skilfully planned arrest of Egmont and Hoorn, than he proceeded to erect an extraordinary tribunal, which had no legal standing except such as the arbitrary will of the duke conferred upon it.