A Spanish fleet of 21 ships, including 10 galleons, was led by Don Juan Álvarez de Avilés.

Twenty from the Dutch fleet were ordered to focus on the Spanish galleons while the rest attacked the smaller vessels.

The battle was a leading driver of the Twelve Years' Truce, under which the Dutch Republic achieved de facto recognition by the Spanish Crown.

The battle had an important indirect effect on the History of Ireland, specifically the key event known as "Flight of the Earls".

The destruction of the Spanish fleet ruled out any such option, and the Earls found themselves in irrevocable exile – with major consequences for the later history of Ireland, and especially of Ulster.