He was a son of Manuel dos Santos Lima de Arriaga Nunes (1885-1940), a sculptor and son of a medical doctor from Pico Island, Azores, and his Portuguese Brazilian wife, Felicidade Eugénia Martins de Oliveira (1894-1987), daughter and granddaughter of goldsmiths.

[1] Arriaga completed a degree in mathematics and engineering at the University of Porto and then volunteered for the Portuguese Army on 1 November 1935.

Here he petitioned for reforms to the conscription system, as well as training and the integration of paratroopers into the Portuguese Air Force.

Arriaga was a major political figure in the Estado Novo regime before the Carnation Revolution of 25 April 1974 in Lisbon, holding a number of public positions such as Head of the Ministry of Defense Cabinet, Secretary of State for Aeronautics, Professor of the Institute of High Military Studies, President of the Nuclear Energy Joint Commission and Executive President of the oil company Angol SA.

1932), Dame Commander of the Order of the Holy Sepulchre, daughter of Mário Formigal (1899-1954), a landowner and son of another, and his wife (m. 1922) Maria Adelaide Rosado Fernandes (1903-1981), of a family of farmers and landowners in Évora, Alto Alentejo, by whom he had five children, including the second wife of former prime minister Pedro Santana Lopes.