was to become the fabled source of wealth it has assumed in legend. The Spanish left mining to private enterprise but instituted a tax known as the "quinto real" whereby a fifth of the metal was collected by the government. The Spanish were quite successful in enforcing the tax throughout their vast empire in the New World; all bullion had to pass through the House of Trade in Seville, under the direction of the Council of the Indies. The supply of Almadén mercury, vital to extracting silver from the ore, was controlled by the state and contributed to the rigor of Spanish tax policy. Inflation - both in Spain and in the rest of Europe - was primarily caused by debt, but a level of debt made possible later by the rising silver imports; Charles had conducted most of his wars on credit, and in 1557, a year after he abdicated, Spain was forced into its first debt moratorium, setting a pattern that would be repeated with ever more disruptive economic consequences. Few Spaniards initially gave a thought to the wholesale slaughter, enslavement, and forced conversion of Native Americans either, although some men such as Bartolomé de las Casas argued for more humane treatment of them. This led to much debate and governmental action. The Laws of Burgos, the New Laws, and other legal and institutional changes somewhat alleviated conditions for Native Americans, including the freeing of all Native American slaves. Faced with the growing threat of piracy, in 1564 the Spanish adopted a convoy system far ahead of its time, with treasure fleets leaving America in April and August. The policy proved efficient, and was quite successful. Only two convoys were captured; one in 1628 when it was captured by the Dutch, and another in 1656, captured by the English, but by then the convoys were a shadow of what they had been at their peak at the end of the previous century. Nevertheless, even without being completely captured they frequently came under attack, which inevitably took its toll. Not all shipping of the dispersed empire could be protected by large convoys, allowing the Dutch, English and French privateers and pirates the opportunity to attack trade along the American and Spanish coastlines and raid isolated settlements. This became particularly savage from the 1650s, with all sides falling to extraordinary levels of barbarity, even by the harsh standards of the