TREATY OF TORDESILLAS
Why did they sail to the west?
On June 7, 1494, the crowns of Spain and Portugal agreed to the Treaty of Tordesillas, named for the city in Spain in which it was created. The Treaty of Tordesillas neatly divided the “New World” of the Americas between the two superpowers. Spain and Portugal divided the New World by drawing a line in the Atlantic Ocean, about 370 leagues west of the Cape Verde Islands, then controlled by Portugal. All lands east of that line were claimed by Portugal. All lands west of that line were claimed by Spain.
For that time the roundness of the earth was already known and it was known that by navigating both in one direction or another, east or west, one could reach the same place on the globe. However, in order to conquer and add to its kingdom the Moluccan Islands, the Crown of Castile had to complete its conquest by directing its naos west of that line, so it was not only to get there, but mainly, from where to get there. That was the reason why Magellan set course for the Moluccas in a westerly direction, an extremely complicated trip. At that time there were no navigational charts from that unexplored area of the world. The expedition encountered a much longer route than expected. They realized that the earth was much bigger than they thought.
When it was time to head home, Elcano, who was already in charge of the expedition after Magellan’s death, decided not to return by the route they had taken. Too long and complicated. He would drive the only nao that remained, the Victoria, along the Portuguese route. He continued sailing to the west, as he had been doing until then. Three years after leaving, the expedition managed to return to Seville. They had completed the first circumnavigation of history.