In Lisbon, on 17 March 1939, a few days before the end of the Spanish Civil War, Portuguese Prime Minister António de Oliveira Salazar and Spanish Ambassador Nicolás Franco sign the Portuguese–Spanish Treaty of Friendship and Non-Aggression (Iberian Pact / Pacto Ibérico). Ratifications are exchanged on 25 March 1939. The languages are Spanish and Portuguese.

Article 1: the parties respect each other’s borders and territories and will not commit acts of aggression against each other. Article 2: they will not assist aggressors acting against each other. Article 3: they will not enter pacts or alliances threatening each other. Article 4: the treaty remains in force even if a party concludes other alliances. Article 5 sets a ten-year duration with ten-year extensions. Article 6 ties entry into force to the exchange of ratifications.

Talks began in September 1938 (Munich Crisis); the final draft, prepared by Luís Teixeira de Sampaio, was proposed to Spain on 9 February 1939. Portugal had backed Franco’s Nationalists throughout the war; Salazar also sought some diversification beyond exclusive reliance on the United Kingdom, without cancelling the Anglo-Portuguese Alliance.

An additional protocol of 29 July 1940, after the Fall of France, reinforced neutrality and consultations. The pact proved decisive in keeping the Iberian Peninsula out of Hitler’s continental system. It was renewed and expanded in 1948; in 1958 it gained a mutual-defence dimension; it was renewed again in 1970.

After the Carnation Revolution (1975), Spínola unsuccessfully sought to invoke the pact for Spanish intervention. In 1977 it was replaced by the Treaty of Friendship and Cooperation between Spain and Portugal after both countries democratised.

The Iberian Pact of 17 March 1939 remains the non-aggression treaty that structured Lisbon–Madrid relations through the Salazar and Franco dictatorships.

Image: map of Spain and Portugal; Wikimedia Commons. Cropped to 16:9.

Source consulted: Iberian Pact. Treaty text: Peninsular Purpose: Portugal and Its 1939 Treaty of Friendship and Non-Aggression with Spain (Halstead).