After 1285 the term portolan (derived from Latin pontus: port) was originally used to refer to a book with nautical information. The expression also served as a reference for sea charts after the 16th century. These maps outlined the coastlines, ports, cliffs and shoals as well as the information needed to navigate the ships. At the beginning of the 15th century portolans replaced the theologically-oriented Mappa Mundi (world map). In the course of the establishment of portolans some places like Pisa, Genoa, Mallorca or Venice became important centers of map production. Apart from meeting the high demand for "every-day maps", these cities also provided individual representational pieces - skilfully made and expensive.