Portuguese atlas page. 16th century Portuguese text and illustrations of a compass rose (bottom) and a human figure (upper left) on an atlas page. Atlases such as these were used during the Age of Discovery that opened the maritime trading route from Europe to India. The text at top right refers to the 'Rules of the North', which involved use of the diagram at upper left to correct calculations of latitude from the height of the Pole Star above the horizon. This page is from a 1563 atlas by the Portuguese cartographer Lazaro Luis. The language used at the time was Old Portuguese. The atlas is held at the Sciences Academy of Lisbon.