Half a century of continual war and more than a century of depredations by privateers and pirates weighed heavily on the administration and defence of the Portuguese empire, spread as it was across Asia, Africa and America, and exhausted the Portuguese treasury. In 1640, Count-Duke de Olivares, royal favourite of Philip IV and prime minister of Spain, imprudently chose to levy a special tax upon Portugal in violation of its constitution, at the very time when the Catalans, a merchant people like those of Lisbon, and also oppressed by Castilian taxes, were on the verge of armed rebellion. Then the prime minister of Portugal, Miguel de Vasconcelos, on the advice of the Spanish nobility, and with the complicity of the Portuguese feudal nobles, announced the Spanish minister's intention of abolishing the Portuguese Cortes, and of making the country a mere province of Castile with its own representatives in the Castilian Cortes. This provocation was the last straw for those Portuguese who desired the restoration of Portugal's independence.