In the second year of the war, 1666, De Ruyter won the hard-fought Four Days' Battle of 1 to 4 June 1666. The division of the English fleet gave the Dutch the advantage of numbers on the first and second days of fighting. An English attack on the anchored Dutch fleet on the first day was resisted and, after two days fighting, the English fleet retreated towards the Thames. However, the English fleet was reinforced by a squadron of undamaged ships on the third evening and fought strongly on the fourth day, so that Tromp seemed near to defeat in the afternoon, until De Ruyter decided the battle with a surprise all-out attack that demoralised his opponents into retreat.