 Complete the following phrase:  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 