&e idea of the martyr as the perfect 'guration of the Christian hero is one of the founding marks of Christianity. &e concept of Crusade stems from a centennial evolution of religious and political thought in the West that culminated in the association of death in combat with martyrdom. &e aggressiveness assumed by the Crusades is justi'able only with the gradual involvement of the Christian religion in the political sphere and the violent shocks caused by the launch of the Islamic jihad since the seventh century. In the Iberian Peninsula, the Crusade had a speci'c colour, only belatedly in(uenced by the ideas of northern Europe. &e Portuguese tradition of chivalry and Crusade was deepened by the Avis dynasty and linked to the Expansion, where the goal of “spreading Christianity” assigned to the political-military agents the heroic status of both warriors and missionaries. &e 'rst siege of Diu was therefore inscribed by Damião de Góis in the crusading e+ort, and his hero António da Silveira is depicted urging his garrison to join him in martyrdom.