The king was fitting out a powerful fleet to carry the war to the coasts of Sweden, and for its equipment had commanded a reinforcement of men and provisions to be sent from Dunkirk.

A fleet accordingly set sail, but were attacked by Von Tromp, some captured, the remainder forced to retire within the harbor again.

Soon after, Tromp seized three English [neutral] ships carrying 1070 Spanish soldiers from Cadiz to Dunkirk; he took the troops out, but let the ships go free.

Leaving seventeen vessels to blockade Dunkirk, Tromp with the remaining twelve advanced to meet the enemy's fleet on its arrival.

It was soon seen entering the Straits of Dover to the number of sixty-seven sail, and having two thousand troops.