Collection: Osher Collection
Name: Descripcion de las Yndias Ocidentalis
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Dimensions: 23 x 32 cm.
Historical Context: Marking charts with limits of the sun's declination to determine latitude, and lines of latitude and longitude as a grid on which to locate position, were not the only guides navigators used in crossing the open seas. Yet another invisible line divided the ocean. Neither astronomical, nor mathematical in origin, this line was a political one, placed by Papal Bull (decree) and mutual consent of the two great Iberian powers--Spain and Portugal. As their mariners ventured westward into the uncharted Atlantic to seek riches and expand their sovereigns' empires, they encountered new lands, and sought validation of possession from the Vatican. Regarded by Christian nations as the ultimate global sovereign power, the Papacy of Rome had the right to divide the newly discovered world. Spain and Portugal justified their requests for ownership because "as crusaders, they were doing the Church's work and therefore entitled to some secular perquisites." Each island group discovered required new lines to be drawn across the Ocean Sea (as the Atlantic Ocean was then called) marking the territorial limits of Spain and Portugal. None of the divisions created by a series of papal bulls was totally acceptable; either they gave away too much land to one power, or took away dominion from a power whose ownership had already been established. Finally, for the sake of peace and accord, Spain and Portugal resolved their differences independent of the papacy. They reached a compromise in the 1494 Treaty of Tordesillas, wherein a line was drawn from the Arctic to the Antarctic Poles at a distance of 370 leagues west of the Cape Verde Islands. Each power agreed that all lands on the eastern side of the line belonged to the King of Portugal and his successors, while all other lands belonged to the King and Queen of Spain. Dividing the world between themselves prevented incursion into the southern oceans of the vessels of other nations. If England and France wished to reach the East Indies, they could do so only by finding a route north of Canada (the Northwest Passage) or over the top of Norway and Russia (Northeast Passage). At times, the line of Tordesillas, known as Meridianus particionis, was used as a prime meridian.