The Treaty of Tordesillas of 7 June 1494 involves agreements between King Ferdinand II of Aragon and Queen Isabella I of Castile and King John II of Portugal establishing a new demarcation line between the two crowns, running from pole to pole, 370 leagues to the west of Cape Verde islands. The Treaty was finally signed following complex diplomatic negotiations between ambassadors and barristers from both Kingdoms. Modification of a demarcation line dividing the world between Spain and Portugal resulted in the birth of Brazil as its eastern end fell within the Portuguese zone. This document is essential if we are to understand American history and economic and cultural relations between Europe and America. Therefore the treaty became an important reference not only to the Atlantic Ocean history but also to the memory of the world allowing the meeting of continents and civilizations separated by unknown oceans.