He was much troubled by attacks of gout, which frequently prevented him from taking his place in the field.

In 1639 there were no military events of importance; nevertheless this year was a memorable one in the annals of the Dutch republic.
It was the year of the battle of the Downs.

A great effort was made by Spain to re-establish her naval supremacy in the narrow seas, and the finest fleet that had left the harbours of the peninsula since 1588 arrived in the Channel in September, 1639.

It consisted of seventy-seven vessels carrying 24,000 men, sailors and soldiers, and was under the command of an experienced and capable seaman, Admiral Oquendo.

His orders were to drive the Dutch fleet from the Channel and to land 10,000 men at Dunkirk as a reinforcement for the Cardinal Infante.