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.
Fortress of São João Baptista (Angra do Heroísmo)
At the outbreak of the First World War, Portugal was a neutral nation, but this progressively changed due in most part to its concerns over its dependencies and economic blockades with its main markets. Following a request by England to detain German nationals, Germany declared war on Portugal (which was reciprocated on 9 March 1916). The original detainees and subsequent German nationals were transferred to the Fortress of São João Baptista between 1916 and 1919 (the end of the War).