The camps and trenches of the besiegers were flooded out; and (October 8) the siege was raised and the army of Don Frederick retired, leaving Alkmaar untaken.

Within a week another disaster befell the Spanish arms.

Between Hoorn and Enkhuizen the fleet of Bossu on the Zuyder Zee was attacked by the Sea-Beggars and was completely defeated.
Bossu himself was taken prisoner and was held as a hostage for the safety of Ste Aldegonde, who fell into the hands of the Spaniards about month later.
This naval victory, following upon the retreat from Alkmaar, strengthened greatly the efforts of Orange and gave fresh life to the patriot cause.

It likewise marked the end of the six years of Alva's blood-stained rule in the Netherlands.

Weary and disappointed, always hampered by lack of funds, angry at the loss of the king's confidence and chafing at the evidence of it in the presence of Medina-Coeli at his side, the governor-general begged that he might be relieved of his functions.