Portugal during World War II
Upon the start of World War II in 1939, the Portuguese Government announced on 1 September that the 600-year-old Anglo-Portuguese Alliance remained intact, but that since the British did not seek Portuguese assistance, Portugal was free to remain neutral in the war and would do so. In an aide-mémoire of 5 September 1939, the British Government confirmed the understanding. As Hitler's occupation swept across Europe, neutral Portugal became one of the Continent's last escape routes. Portugal managed to remain neutral throughout the war despite extraordinary pressures from both sides, notably over the strategically located Azores islands and over the wolfram (tungsten) trade.
War tax stamp
After Portugal entered World War I in March 1916, several of its colonies issued war tax stamps as well. Most of these were produced by overprinting "TAXA DE GUERRA" on existing stamps, though Mozambique issued a set of two which depicted allegorical figures of History and the Republic. The Portuguese colonies of Macao, Mozambique, Portuguese Africa, Portuguese Guinea, Portuguese India and Timor issued war tax stamps.