While Milton was busy with his verse events were moving fast in favour of the cause which he saw trodden under foot. Defeat had only spurred the Dutch to fresh efforts. Their best seaman, De Ruyter, had reorganized their fleet, and appeared off the North Foreland in May 1666, with eighty-eight vessels, stronger and better armed than those of Opdam. The English fleet was almost as strong; but a squadron had been detached under Prince Rupert to meet a French force reported to be at Belleisle, and it was with but sixty ships that the new admiral, Monk, Duke of Albemarle, fell in with De Ruyter's armament. There was no thought however of retreat, and a fight at once began, the longest and most stubborn that the seas have ever seen. The battle had raged for two whole days, and Monk, left with only sixteen ships uninjured, saw himself on the brink of ruin, when on the morning of the third he was saved by the arrival of Rupert. Though still greatly inferior in force, the dogged admiral renewed the fight on the fourth day as the Dutch drew off to their own coast, but the combat again ended in De Ruyter's favour and the English took refuge in the Thames. Their fleet was indeed ruined; twenty ships had been taken or sunk and a far larger number disabled; but the losses of the enemy had been hardly less. What the Dutch had discovered, owned De Witt, was, "that English sailors might be killed and English ships burned, but that there was no conquering Englishmen." At the close of July in fact the two fleets, again refitted, met anew off the North Foreland; and a second fight, as hard fought as that which had gone before, ended in an English victory. Twenty Dutch sail had struck or sunk, seven thousand Dutch seamen had been slain, while the English loss was comparatively small. The victorious fleet sailed along the rich coast of Holland, burning merchantmen and plundering its undefended towns. But Holland was as unconquerable as England herself. In a short time the Dutch fleet was again refitted and at sea, and Lewis, whose aid had hitherto been only in words, thought it time to act. The French fleet joined the Dutch, and the English found themselves too inferior in force to venture on a fresh battle for the command of the Channel.