The duration of such long dictatorship in Europe, which, just like the Spanish of Francisco Franco, survived yet another thirty years after the defeat of the nazi-fascists in WorldWar II, has been studied in detail and is at the centre of a major historiographical debate in the recent years. Indeed, historians are trying to glimpse the reasons for such sustainability, certain that they are multiple, external and internal in character, as the long durability of both Iberian regimes occurred – it should be recalled, during the cold war period at a world and European scale. These are some of the questions we would like to address in this meeting: Was the longevity of the dictatorship a result of the structural conditions of the Portuguese society, with industrialization and urbanization occurring rather belatedly?; What was the role of the regime, of its institutions and of its lead mentor, the ditactor Oliveira Salazar, on the long-term nature of the Portuguese Estado Novo?; Did the repressive structure, namely the political police – PVDE/PIDE/DGS – play a central role on the sustainability of the dictatorial regime?; How did other institutions, such as the Catholic Church and the Armed Forces, collaborate with the regime?; What was the role of the colonial war and of the military structure on the longevity of the regime?; Did the Cold War international situation reinforce the role of a dictatorship essentially anticommunist? If so, how?