The celebrations of the 5th centenary of Brazil's discovery present a privileged opportunity to deepen the understanding and friendship between those two countries and to emphasize the importance of their common history. Efforts have been made in order to systematize and give forth the documents of interest to the history of both countries. A brief survey of the documentary fonds of the IAN/TT, concerning the history of colonial Brazil was made in this work. In the article the author presents inedited or new working perspectives for two of those fonds namely the Trade Companies of 'Grão Pará' and 'Maranhão' and of 'Pernambuco' and 'Paraíba' and of the Court of the Holy Office. Researchers are invited to ‘grub up’ such an important archival material.