Between the 14th and early 17th centuries, portolan (or pilot-book) charts provided the main navigational aids between the seaports of the world. The term portolan (from the Italian 'portolano') refers to written sailing directions for seafarers. By networks of lines indicating the direction of one port from another, navigators were able to set their necessary courses. From such works, accumulated over generations, the first marine charts were drawn. Now the charts are admired as much for their decorations as their historical information. Most portolan charts of the Mediterranean were compiled in Genoa, Venice, and Majorca.