Resembling our American Revolution in the character of the struggle as well as the issues at stake--though it was far more bloody and desperate--the Dutch War of Independence was fought mainly within the country itself, with the population divided, and the Spanish depending on land forces to maintain their rule; but, as in the American war, control of the sea was a vital factor. For munitions, supplies, gold, for the transport of the troops themselves, Spain had to depend primarily on the sea. It is true one could continue on Spanish territory from Genoa, which was Spain's watergate into Italy, across the Mont Cenis Pass, and through Savoy, Burgundy, Lorraine, and Luxembourg to Brussels, and it was by this route that Parma's splendid army of 10,000 "Blackbeards" came in 1577. But this was an arduous three months' march for troops and still more difficult for supplies. To cross France was as a rule impossible; when Don Juan of Austria went to Flanders for the brief period of leadership ended by his death of camp fever in 1578, he passed through French territory disguised as a Moorish slave. By the sea route, upon which Spain was after all largely dependent, and the complete control of which would have made her task infinitely easier, she was constantly exposed to Huguenot, Dutch, and English privateers. These gentry cared little whether or not their country was actually at war with Spain, but took their letters of marque, if they carried them, from any prince or ruler who would serve their turn. With this opportunity to strike at Spanish communications, it will appear strange that the Dutch should not have immediately seized their advantage and made it decisive. One curious difficulty lay in the fact that throughout the war Dutch shipping actually carried the bulk of Spanish trade and drew from it immense profits. Even at the close of the century, while the war was still continuing, nine-tenths of Spain's foreign trade and five-sixths of her home trade was in foreign--and most of it in Dutch--hands. Hence any form of sea warfare was sure to injure Dutch trade. The Revolution, moreover, began slowly and feebly, with no well-thought-out plan of campaign, and could not at once fit out fully organized forces to cope with those of Spain. The Dutch early took to commerce warfare, but it was at first semi-piratical, and involved the destruction of ships of their own countrymen.