Portuguese Nautical Master Charts

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 1492, Portuguese cartographers were creating enormous master charts containing all the latest knowledge of coastlines, and oceans.
  • These master charts were regarded as state secrets. Furthermore, many were destroyed by Europe's only tsunami in 2,000 years which hit Lisbon in November 1755.
  • As a result few Portuguese originals (such as Jorge Reinel's) have survived. Most of charts known today are pirated copies collected by jealous Italian competitors including the Cantino (1502) map, the Caverio map (1505), and the Maggiolo (1516) map shown below.
  • The master charts were based on separate local nautical charts.
  • By 1505 and probably earlier as well, each of the major Atlantic ports also had a separate approach chart detailing soundings, dangers, and other information needed to guide sailors safely into port. (Sea and airline pilots today use separate approach charts for each sea and airport.)
Copy Stolen by Vesconte Maggiolo of Portuguese Master Chart of Atlantic and Indian Oceansspy


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