Ostend was the one position in Flanders held by the United Provinces, with a very mixed garrison. The archduke besieged Ostend (1601). Maurice did not attack him, but captured the keys of the debatable land of Cleves and Juliers. The siege of Ostend developed into a tremendous affair, and a school in the art of war. Maurice, instead of aiming at a direct relief, continued his operations so as to prevent the archduke from a thorough concentration. In the summer of 1602 he was besieging Grave, and Ostend was kept amply supplied from the sea, where the Dutch had inflicted a tremendous defeat on the enemy. But early in 1603 the Spaniards succeeded in carrying some outworks. The death of Elizabeth, and the accession of James I. to the throne of England affected the European situation; but Robert Cecil, Lord Salisbury, was the new king's minister. Nevertheless, no long time had elapsed before James was entering upon alliance with the Spaniard. A new commander-in-chief was now before Ostend in the person of Ambrose Spinola, an unknown young Italian, who was soon to prove himself a worthy antagonist for Maurice. Spinola continued the siege of Ostend, where the garrison were being driven inch by inch within an ever-narrowing circle. This year, Maurice's counter-stroke was the investment of Sluys, which was reduced in three months, in spite of a skilful but unsuccessful attempt at its relief by Spinola. At length, however, the long resistance of Ostend was finished when there was practically nothing of the place left. The garrison marched out with the honours of war, after a siege of over three years. The next year was a bad one for Maurice. Spinola was beginning to show his quality. Maurice's troops met with one reverse, when what should have been a victory was turned into a rout by an unaccountable panic. Spinola had learnt his business from Maurice, and was a worthy pupil. All through 1606 the game of intrigue was going on without any great advance or advantage to anyone. But while the Dutch had been campaigning in the Netherlands, they had also been establishing themselves in the Spice Islands, and in 1607 the rise of the United Provinces as a sea-power received emphatic demonstration in a great fight off Gibraltar. The disparity in size between the Spanish and Dutch vessels was enormous, but the victory was overwhelming. Not a Dutch ship was lost, and the Spanish fleet, which had viewed their approach with laughter, was annihilated. The name of Heemskerk, the Dutch admiral who inspired the battle, and lost his life at its beginning, is enrolled among those of the nation's heroes.