Damião de Góis, a prominent figure in the Portuguese Renaissance, was an aristocrat of old and proud roots, whom the experience of childhood and youth in the court of D. Manuel filled with religious and patriotic enthusiasm and imbued with the political ideas defended by the Crown. Formed for royal service with other figures who later dominated the administration of João III, his placement in the rich factory of Antwerp and subsequent diplomatic missions, as well as giving him access to the most select places of the time, widened his horizons: he saw the dangerous circumstances of European politics, identifying detractors, usually opportunistic, of the Portuguese Expansion; and met fascinating personalities, either intellectuals, like Erasmus of Rotterdam, or humanists-diplomats, like Pietro Bembo, he certainly wished to somehow emulate. His university studies enabled him to respond to requests from the Portuguese Crown, to which he remained close even when he seemed a priuatus, such as spreading in Latin, the international language of the time, the news of the victory in the First Siege of Diu.
Indeed, internal and external evidence justifies identifying as source of the Commentarii rerum gestarum in India citra Gangem a Lusitanis anno 1538 the manuscript of the witness Francisco do Couto, entitled "Siege and war of Diu", belonging to the archives of the Casa Fronteira and Alorna and published by Luciano Ribeiro forty years ago. Internally, it is worth noting the adoption of the same perspective and sequence in the presentation of events, and the repetition of names and even mistakes in the same context, the highlight of which is the misconception about the death of Paio Rodrigues de Araújo; externally, the hastened departure of Francisco do Couto to Portugal, and the sending of the text to Leuven, where Góis was located and received other information, probably from the East. The same urgence has led the humanist to translate and adapt, in about two months, the story in order to fit it into humanistic standards and the defense of Portugal's interests; and he managed to publish it in September 1539, ten months after the end of the siege. All this effort seems to indicate an interest on the part of the king himself to spread quickly and effectively news so eagerly awaited in Europe, taking advantage of the personal prestige and the contacts of the humanist of Alenquer, which corroborates the perspective of António José Saraiva on the possible role of Damião de Góis as diplomatic agent of D. João III.
In turn, the Goisian notitia of Diu's victory is integrated into a tripartite work within the partisan discourse of classical rhetoric. The dedicatory letter functions as an exordium, which launches political-religious issues, developed in the Disceptatiuncula (suasoria and invectiva) that closes (peroratio) the work. Pietro Bembo, the recipient of the letter and the peroration, is the arbiter of the situation, whom Góis asks for help (petitio) as a figure capable of influencing opinions. The history of the siege can therefore be seen as probative narratio, in the development of a political thesis corresponding to the official perspectives of the Portuguese Crown. The whole structure of the work looks like a crafted organization, which, coupled with the narrative breuitas, creates verisimilitude. There is a remarkable grasp of Latin, and imitatio underlies the use of classical sources as models, depending on the various genres involved.