paragraph: To protect its seagoing interests and trade routes, Portugal established strategic garrisons in Goa (India), Malacca (East Indies), and Hormuz in the Persian Gulf. Portuguese explorers then embarked upon Macau (now Macao), the Congo, and various other parts of Africa, including the Sudan. The Portuguese policy was to avoid armed strife and to develop a trade empire, rather than to conquer nations. To this end it succeeded with relatively few blood-soaked episodes in its colonial history. Adventures abroad, however, proved disastrous during the second half of the 16th century. In 1557 the 14-year-old boy-king Sebastião ascended the throne, the beginning of a calamitous reign that was to end at the battle of Alcacer-Quiber (Morocco) in pursuit of a vain crusade. Sebastião's untimely demise, alongside some 18,000 ill-prepared, badly led followers, set the stage for a crisis of succession. For many years afterwards, legends and rumors bizarrely insisted that the king was still alive, and imposters turned up from time to time claiming the throne; those who were plausible enough to be deemed a threat were summarily executed. In fact, the only rightful claimant to the crown was the elderly Prince Henry. But after two years of alternating between the throne and his sickbed, he died, heirless. Surveying the situation and smelling an opportunity, Spain occupied the power vacuum, and Portugal's neighbor and long-time antagonist became its master. Spanish rule dictated Portugal's inadvertent involvement in Spain's ongoing wars. In 1587 a squadron of British ships commanded by Francis Drake attacked the Algarve (now a "legitimate target" as Spanish territory) and sacked Sagres, thus depriving the world of the relics of Henry the Navigator. Nine years later Faro was torched. The 1386 Treaty of Windsor, by which Britain and Portugal had pledged eternal friendship, seemed a distant memory. Portugal's empire was gradually eroded, and many of its trading posts (with the notable exception of Brazil) were picked off by the British and Dutch. Finally, after 60 years of Spanish rule, Portuguese noblemen (aided by the French, then at war with Spain) organized a palace coup and restored independence. The Great Disaster Portugal's greatest misfortune struck on All Saint's Day, 1 November 1755. 
answer: Spain's new involvement with Portugal caused Portugal to become enmeshed in Spain's war with Britain and the British attached Portugal