The present paper discusses document translation and analyzes the translation from Portuguese to Spanish of a report of the Council of Portugal, which describes the political-administrative situation of the Moluccas Islands. The concepts of bilingualism and diglossia (FISHMAN, 1967) are used to discuss the colonial translation scenario, and the taxonomic framework provided by Barbosa (2004) supports the translation analysis. The main research tools are the selection and editing of manuscripts, and the classification of translation procedures. Results indicate the historical study of document translation between Portuguese and Spanish as a new research field, mainly involving contact between languages; the tendency towards literality as the main feature of Iberian Union (1580-1640) administrative translation, as these are technical documents; punctual translator interference, with instances of source-text omission and rewriting; and the possible comparison between document translation in Asian and American Portuguese colonies.