Philip's first step, upon assuming the government, was to issue a declaration, through the council of Holland, that the privileges and constitutions, which he had sworn to as Ruward, or guardian, during the period in which Jacqueline had still retained a nominal sovereignty, were to be considered null and void, unless afterwards confirmed by him as count. At a single blow he thus severed the whole knot of pledges, oaths and other political complications, by which he had entangled himself during his cautious advance to power. He was now untrammelled again. As the conscience of the smooth usurper was, thenceforth, the measure of provincial liberty, his subjects soon found it meted to them more sparingly than they wished. From this point, then, through the Burgundian period, and until the rise of the republic, the liberty of the Netherlands, notwithstanding several brilliant but brief laminations, occurring at irregular intervals, seemed to remain in almost perpetual eclipse. The material prosperity of the country had, however, vastly increased. The fisheries of Holland had become of enormous importance. The invention of the humble Beukelzoon of Biervliet, had expanded into a mine of wealth. The fisheries, too, were most useful as a nursery of seamen, and were already indicating Holland's future naval supremacy. The fishermen were the militia of the ocean, their prowess attested in the war with the Hanseatic cities, which the provinces of Holland and Zeland, in Philip's name, but by their own unassisted exertions, carried on triumphantly at this epoch. Then came into existence that race of cool and daring mariners, who, in after times, were to make the Dutch name illustrious throughout the world, the men, whose fierce descendants, the "beggars of the sea," were to make the Spanish empire tremble, the men, whose later successors swept the seas with brooms at the mast-head, and whose ocean-battles with their equally fearless English brethren often lasted four uninterrupted days and nights. The main strength of Holland was derived from the ocean, from whose destructive grasp she had wrested herself, but in whose friendly embrace she remained. She was already placing securely the foundations of commercial wealth and civil liberty upon those shifting quicksands which the Roman doubted whether to call land or water. Her submerged deformity, as she floated, mermaid-like, upon the waves was to be forgotten in her material splendor. Enriched with the spoils of every clime, crowned with the divine jewels of science and art, she was, one day, to sing a siren song of freedom, luxury, and power. As with Holland, so with Flanders, Brabant, and the other leading provinces. Industry and wealth, agriculture, commerce, and manufactures, were constantly augmenting. The natural sources of power were full to overflowing, while the hand of despotism was deliberately sealing the fountain.