This map is part of a series of 12 animated maps showing the history of The Portuguese and Spanish Empires.
The first successful expeditions across the Atlantic Ocean raised the question of what to do with the archipelagos and new lands discovered by these navigators.
In 1479, Portugal and Castile signed an initial treaty confirming Castile’s dominion over the Canaries, while recognizing Portugal’s monopoly on the African coast.
This agreement was confirmed two years later by a Bull issued by the Pope. Portugal could now take possession of all lands south of the parallel crossing through the Canary Islands on condition that they undertake evangelical missions.
Christopher Columbus’ discoveries in 1492 played havoc with this situation, and the following year Spain was given a new Bull from the Pope. This drew a new line along the meridian 100 leagues west of the Azores and the Cape Verde Islands.
Portugal protested and demanded direct negotiations between the two Iberian countries, which led to the Treaty of Tordesillas.
This treaty confirmed that the line ran from North to South, rather than East to West. But, after Portugal claimed that its ships needed to go further into the Atlantic to pick up favourable winds in order to reach the African coasts, it was moved 370 leagues further west of the Azores.
In 1500, during the second Portuguese expedition to the Indies, Pedro Álvares Cabral discovered a new land west of the Portuguese zone.
In the decades that followed, the contours of the New World became increasingly clear to European mapmakers. It became apparent that the Tordesillas line now ran through the middle of the South American continent.
After the voyage by Magellan, who had proved that the Indies could be reached either from the West or from the East, rivalry between Spain and Portugal focused principally on the area around the Spice Islands. This raised the question whether the boundary between the Spanish and Portuguese zones in the Pacific ran along the same meridian identified in the Treaty of Tordesillas. They also needed to know where exactly this meridian passed.
The Treaty of Saragossa, signed in 1529, set a second line dividing the Pacific Ocean approximately 300 leagues east of the Spice Islands. These islands thus remained Portuguese, but Spain was given the right to trade in the Philippines.
No other European power recognized the Treaties of Tordesillas and Saragossa. Once their naval forces were able to rival those of Spain and Portugal, Holland, England and France ignored them.