António de Oliveira Salazar
Despite the authoritarian character of the regime, Portugal did not experience the same levels of international isolation as Spain did following World War II. Unlike Spain, Portugal under Salazar was accepted into the Marshall Plan (1947–1948) in return for the aid it gave to the Allies during the final stages of the war. Furthermore, also unlike Spain, it was one of the 12 founding members of the North Atlantic Treaty Organisation (NATO) in 1949, a reflection of Portugal's role as an ally against communism during the Cold War in spite of its status as the only non-democratic founder. In 1950, Portugal joined the European Payments Union and participated in the founding of the European Free Trade Association (EFTA) in 1960 and the Organisation for Economic Co-operation and Development in 1961. It joined the General Agreement on Tariffs and Trade in 1962, and finally, Portugal signed a free trade agreement with the European Economic Community in 1972, still under the auspices of the "Estado Novo".
Portugal–United Kingdom relations
The 19th century saw the alliance between Portugal and the United Kingdom come into effect once more when Napoleon Bonaparte built the Continental System, which Portugal refused to join, leading Napoleon to invade. In 1807 Napoleon's army attacked Lisbon, forcing the Portuguese royal family to flee to Brazil under the protection of the British Royal Navy. In the later half of the century, as Portugal's imperial power declined following Brazil's independence, there were disputes between itself and the United Kingdom in southern Africa (1890 British Ultimatum) which was a great embarrassment for the Portuguese monarchy and colonial prestige. Portugal was one of the Allies of World War I along with Britain. While officially neutral in World War II, Portugal remained friendly to the British, a counterpart to Spain's cooperation with the Axis.