mattoso earned his doctoral degree in medieval history from the catholic university of leuven, in belgium, in 1966 (with a thesis on the abbey of pendorada - "l'abbaye de pendorada : des origines à 1160"), while he was benedictine monk at the abbey of singeverga. he returned to secular life in 1970, and taught at the university of lisbon and at the new university of lisbon. he was also a director of national archives / torre do tombo.