Nautical charts are an important tool for seafarers, providing them with more rigorous information about their position. In Portugal, the existence of numerous cartographers of the highest professional level was a key factor to the success of the Portuguese Discoveries, in the fifteenth and sixteenth centuries. There were several families of cartographers with international recognition, and their expertise was often used to train other European cartographers. Several of these Portuguese cartographers were even invited to work abroad.
The Maritime Museum has a very interesting collection of nautical charts. Some of them are real treasures, both for their antiquity and their rich illustrations. This collection includes many illuminated manuscripts on parchment dating from a long period of time between the sixteenth and the eighteenth century.