A World to Share:
Beginning in the 15th century, in a time when all European powers were at war, the Kingdom of Portugal set off on maritime expeditions towards the West, which brought them to Cape Verde, and towards the south along the African coasts in search for a passage to the Indies.
These expeditions were funded by the papal powers, who, in 1481, enacted the papal bull "Aeterni regis ". This legal certificate granted Portugal the right to appropriate all discovered territories, and all kingdoms who wished to challenge that notion risked excommunication.
This expedition forced Castilians (Spain), the other maritime power at the time, to explore the West in search of a route to the Indies. The Castilian expedition, led by Christopher Columbus, returned to Spain after discovering the Caribbean to claim his pre-emptive right of these new territories.
The King and Queen of Castile supported Christopher Columbus and brought the matter to Pope Alexander IV Borjia. Being of Spanish descent, the pope worked in favor of the Castilians and abrogated the old papal bull, replacing it with the bull "Inter Catera". The new bull was heavily bias towards Spain, and accorded them sovereignty over all the lands located at 100 leagues to the West of the Acores Islands.
A compromise fair to one but not to all
The Portuguese King Jean II was very displeased with this new demarcation. He strongly protested against the divide which left only a small margin of land on the African coasts for the Portuguese explorers to work with. War seemed to be the only method of solving tensions between the Spanish and Portuguese.
The two kingdoms, aware that a war in the Iberian Peninsula would only weaken both their states to the benefit of other European powers, decided to negotiate instead. On June 7, 1494, they came to an agreement and signed the Treaty of Tordesillas. They decided to split the world between Spaniards and Portuguese, using the North-South axis from pole to pole as a guide.
All territories located at more than 370 leagues to the West of the Acores Islands were accorded to the Spanish. With the new division (relative to the measuring systems at the time), the eastern point of South America belonged to the Portuguese. On April 22, 1500, the Portuguese arrived in Brazil to establish their foundations in a country which today, is the only one of 20 South American countries who acknowledges Portuguese, and not Spanish as their native language.
A treaty that does not hold up against the power of other rising kingdoms
While European kingdoms continued developing their power, they also began turning their attention to the seas, and saw that the Spanish kingdoms were crumbling to manage the gold mine that was the Americas.
The French King François 1st complained about the treaty of Tordesillas arguing that "the sun shines for me like it does for others. I would like to see the clause of Adam's testament that excludes me from my share of the world."
The French sovereign was able to obtain a more lenient version of the treaty from Pope Clément VII, who recognized that the law was only applicable to discovered territories, but not to regions that were to be discovered in the future. In 1534 French sailors thus set off on an adventure. The following year, Jacques Cartier discovered Canada.
The Spanish and Portuguese were vehemently opposed to having other countries set sail in what they considered to be their space, but they had no choice but to accept. The treaty of Tordesillas which worked for so long in their favor, began to crumble little by little until it disappeared in the first half of the 17th century.