The Doctrine of Discovery and Papal Authority

When European powers began their overseas expansion in the 15th century, they operated under a principle that granted them the right to claim lands inhabited by non-Christian peoples. This concept, later formalized as the “Doctrine of Discovery,” justified colonization by framing indigenous territories as terra nullius—land belonging to no one. The Catholic Church played a crucial role in legitimizing these claims. As early as 1454, Pope Nicholas V issued a bull authorizing Portugal to seize lands discovered along the African coast en route to India.

The rivalry between Spain and Portugal intensified after Columbus returned from his 1492 voyage, mistakenly believing he had reached the East Indies. Fearing Portuguese counterclaims, Spain urged Pope Alexander VI to recognize its exclusive rights. On May 4, 1493, the pope drew the Line of Demarcation, dividing the unexplored world between the two powers: territories west of a line 100 leagues west of the Azores and Cape Verde went to Spain, while those east went to Portugal.

The Treaty of Tordesillas and Its Consequences

The 1494 Treaty of Tordesillas adjusted the papal line by moving it 270 leagues farther west. This modification had a lasting geopolitical impact: it granted Portugal claim over Brazil, which lay east of the revised boundary. Meanwhile, Spain secured rights to most of the Americas. The treaty exemplified how European powers, with papal endorsement, partitioned the globe without consulting indigenous nations.

Portugal’s success in the spice trade following Vasco da Gama’s voyage to India (1497–1499) spurred other European nations to seek alternative routes to Asia. Despite Columbus’s failed attempts to reach China by sailing west, hope persisted that a passage might exist through the newly discovered lands. This ambition drove 16th-century explorers like Amerigo Vespucci, John Cabot, and Ferdinand Magellan.

Magellan’s Perilous Circumnavigation

Magellan, a Portuguese navigator sailing for Spain, became the first to find a westward route to Asia. His 1519 expedition aimed to claim the Spice Islands (Moluccas) for Spain, arguing they lay within its hemisphere under the Tordesillas division. Commanding five ships, Magellan navigated the treacherous strait now bearing his name in October 1520. After enduring starvation, scurvy, and mutiny, his fleet reached the Philippines in March 1521, where Magellan was killed in battle.

Only one ship, the Victoria, completed the journey, returning to Spain in September 1522 with a cargo of spices valuable enough to fund the entire expedition. Despite this feat, Spain’s subsequent efforts to challenge Portuguese dominance in the Moluccas failed, leading to the 1529 Treaty of Zaragoza, where Spain relinquished its claims in exchange for 350,000 ducats.

The Conquistadors and the Fall of Indigenous Empires

The early 16th century marked the era of the conquistadors. Hernán Cortés’s 1519 expedition against the Aztec Empire demonstrated how small forces could topple advanced civilizations. With just 600 men, Cortés exploited local rivalries and Aztec Emperor Moctezuma II’s initial hospitality before besieging Tenochtitlán. By 1521, the city lay in ruins, paving the way for Spanish rule over Mexico.

Similarly, Francisco Pizarro’s 1532 conquest of the Inca Empire relied on deception and violence. After capturing Emperor Atahualpa and executing him despite receiving a massive ransom, Pizarro seized Cusco and established Lima as Peru’s capital. These conquests opened the continent to further exploitation, with expeditions like Coronado’s search for the Seven Cities of Gold expanding Spanish knowledge of North America.

Colonial Administration and Indigenous Exploitation

By 1550, Spain had established a bureaucratic system to govern its colonies. The Council of the Indies oversaw appointments, while viceroys in Mexico City and Lima administered vast territories. The encomienda system granted settlers control over indigenous labor, often leading to abuse despite royal regulations aimed at protection.

Bartolomé de las Casas, a Dominican friar, became a vocal critic of colonial brutality, advocating for indigenous rights. His writings exposed the atrocities committed under the guise of conversion and civilization.

Economic Exploitation and Global Impact

Spain’s colonies became a source of immense wealth, particularly through silver mines in Potosí (modern Bolivia) and Zacatecas (Mexico). Between 1503 and 1660, over 18,000 tons of registered silver flooded Europe, fueling inflation and transforming global trade. Agricultural enterprises, including sugar plantations reliant on enslaved Africans, further enriched the empire.

Legacy of the Conquest

The Spanish and Portuguese empires set precedents for European colonialism, embedding racial hierarchies and extractive economies in the Americas. The Treaty of Tordesillas’s arbitrary divisions ignored indigenous sovereignty, a mindset that persisted for centuries. Today, debates over reparations and historical justice continue to grapple with this era’s enduring consequences.

The conquests also reshaped global demographics, cultures, and ecosystems through the Columbian Exchange, which transferred crops, animals, and diseases between continents. While Spain’s empire eventually declined, its colonial structures influenced modern Latin American societies, leaving a complex legacy of cultural fusion and systemic inequality.

In retrospect, the Age of Conquest was not merely a series of expeditions but a transformative epoch that redefined power, faith, and exploitation on a global scale. Its echoes remain audible in contemporary discussions about imperialism, identity, and restitution.