Portuguese Nautical Master Maps

Beginning in the 1440s, Portuguese ships ventured further and further into the Atlantic and down the Southern coast of Africa., first accumulating knowledge of the South Atlantic (by 1487), then the Mozambique channel (by 1497) and by 1502 Brazil and Canada (the New World). After every expedition, map-makers for Portuguese kings incorporated information from the most recent voyages of exploration. By 1502, Portuguese cartographers were creating enormous master maps containing all the latest knowledge of coastlines, and oceans. Because these master maps wer e regarded as state secrets--few Portuguese originals (such as Jorge Reinel's below) have survived. Most of maps known today are pirated copies collected by jealous Italian competitors--the Cantino (1502) map (available in print only) and the Maggiolo (1516) map shown below. These master maps were probably used to create separate nautical charts for different regions.
By 1505 and probably earlier as well, each of the major Atlantic ports also had a separate approach chart de tailing soundings, dangers, and other information needed to guide sailors safely into port. Sailors and airline pilots today use separate approach charts for each sea and air-port.

The Navigator's World in 1525: Jorge Reinel's Atlantic Master Map
The Navigator's World in 1440: Primitive Nautical Charts of Europe and North AfricaThe Navigator's World in 1516: Maggiolo's (pirated) Master of the Atlantic and Indian Oceans
How Good Were Those Maps?	In 1440	In 1516

All Sepia Maps © Huntington Library