For an ambition so inclusive, the American revenue was essential indeed. And in the second half of the century it reached a substantial figure. The yearly output of the mines rose to about eleven million _pesos_ per annum, and the amount which the king received for his share, between the years 1560 and 1600, was probably on an average not far from one and three quarters millions, while at the same time other sources of revenue from America became of considerable importance. It was a goodly sum for those days, but it was not enough for the king's needs. When Charles abdicated, the imperial treasury was indebted in the sum of ten millions sterling; and much of the bullion which was carried by the treasure fleets that plied regularly between Porto Bello and Cadiz was pledged to German or Genoese bankers before it arrived, while some of it found its way into the pockets of corrupt officials. What remained for the king, together with the last farthing that could be wrung from his Spanish and Italian subjects, was still inadequate, to his far-reaching designs; and Philip II, reputed the richest sovereign in Christendom, was often on the verge of bankruptcy. It was a disconcerting fact, indeed, that although Spain and Portugal had divided the world between them, the thrifty Dutch seemed to reap the major profits of their discoveries. Within half a century Antwerp had risen to be the chief _entrepot_ and financial clearing-house of western Europe. English wool was marketed there, and there English loans were floated. There Portuguese spice cargoes, purchased while still at sea, were brought to be exchanged at high prices for the gold and silver that found its way into the hands of Spain's creditors in Germany, Italy, and France. A wealthy people were these Dutch subjects of Philip II; subjects, yet half free, escaping his control. It was intolerable that the Netherlands, infested with heresy, drawing their wealth from the enemies of Spain, and from Spain itself, should not contribute their share to the service of the empire. To control the Netherlands and to divert the profits of Dutch trade into the Spanish treasury was thus an essential part of Philip's policy. When the Duke of Alva left for Brussels in 1567 he promised to make the Netherlands self-supporting and to extort from them an annual revenue of two million ducats. But the methods of Alva were destined to failure. He was a better master of war than of finance, and by ruining Dutch trade he killed the goose that laid the golden egg. The Southern Netherlands were finally conciliated by a more skillful policy than any known to Alva; but the city of Antwerp never recovered from the ruin which Philip's unpaid soldiers inflicted upon it in 1576, and when the war was over, the commercial and industrial activities which had made it prosperous were to be found in Amsterdam in the independent Netherlands, and in London across the Channel.