Voyages of Christopher Columbus

Between 1492 and 1504, the Italian explorer and navigator Christopher Columbus led four transatlantic maritime expeditions to the Americas in the name of the Catholic Monarchs of Spain. These voyages led to Europeans learning about the New World and were an early breakthrough in the period known in Europe as the Age of Exploration, which saw the colonization of the Americas, a related biological exchange, and the beginning of trans-Atlantic trade. These events, the effects and consequences of which persist to the present, are often cited as the beginning of the modern era. Born in the Republic of Genoa, Columbus was a navigator who sailed in search of a westward route to India, China, Japan and the Spice Islands thought to be the East Asian source of spices and other precious oriental goods that were otherwise obtainable only through arduous overland routes. Columbus was partly inspired by the 13th-century Italian explorer Marco Polo in his ambition to explore Asia. His initial belief that he had reached "the Indies" has resulted in the name "West Indies" being attached to the Bahamas and the other islands of the Caribbean. At the time of Columbus's voyages, the Americas were inhabited by Indigenous Americans, and Columbus later participated in the beginning of the Spanish conquest of the Americas. Columbus died in 1506, and the next year, the New World was named "America" after the Italian explorer Amerigo Vespucci, who realized that it was a unique landmass. The search for a westward route to Asia was completed in 1521, when the Magellan expedition sailed across the Pacific Ocean and reached Southeast Asia, before returning to Europe and completing the first circumnavigation of the world.

Background Many Europeans of Columbus's day assumed that a single, uninterrupted ocean surrounded Europe, Asia and Africa, although Norse explorers had colonized areas of North America beginning with Greenland c. 986. The Norse maintained a presence in North America for hundreds of years, but contacts between their North American settlements and Europe had all but ceased by the early 15th century. Until the mid-15th century, Europe enjoyed a safe land passage to China and India—sources of valued goods such as silk, spices, and opiates—under the hegemony of the Mongol Empire (the Pax Mongolica, or "Mongol Peace"). With the Fall of Constantinople to the Turkish Ottoman Empire in 1453, European countries sought to compete with the Silk Road dominated by the gunpowder empires through expanded use of ocean voyages to scope out and establish new trade routes. Portugal was the main European power interested in pursuing trade routes overseas, with the neighboring kingdom of Castile — one of the predecessor kingdoms of present-day Spain — having been somewhat slower to begin exploring the Atlantic because of the land area it had to reconquer from the Moors during the Reconquista. This remained unchanged until the late 15th century, following the dynastic union by marriage of Queen Isabella I of Castile and King Ferdinand II of Aragon (together known as the Catholic Monarchs of Spain) in 1469, and the completion of the Reconquista in 1492, when the joint rulers conquered the Moorish kingdom of Granada, which had been providing Castile with African goods through tribute. The fledgling Spanish empire decided to fund Columbus's expedition in hopes of finding new trade routes and circumventing the lock Portugal had secured on Africa and the Indian Ocean with the 1481 papal bull Aeterni regis.

Navigation plans In response to the need for a new route to Asia, by the 1480s, Christopher and his brother Bartholomew had developed a plan to travel to the Indies (then construed as roughly all of southern and eastern Asia) by sailing directly west across what was believed to be the singular "Ocean Sea", the Atlantic Ocean. By about 1481, Florentine cosmographer Paolo dal Pozzo Toscanelli sent Columbus a map depicting such a route, with no intermediary landmass other than the mythical island of Antillia. In 1484 on the island of La Gomera in the Canaries, then undergoing conquest by Castile, Columbus heard from some inhabitants of El Hierro that there was supposed to be a group of islands to the west. A popular misconception that Columbus had difficulty obtaining support for his plan because Europeans thought the Earth was flat can be traced back to a 17th-century campaign of Protestants against Catholicism. This view was popularized in works such as Washington Irving's 1828 biography of Columbus. Knowledge that the Earth is spherical was actually widespread, having been the general opinion of ancient Greek science and gaining support throughout the Middle Ages (for example, Bede mentions it in The Reckoning of Time). The primitive maritime navigation of Columbus's time relied on regular observations of both the stars and the curvature of the Earth.

Diameter of Earth and travel distance estimates

Eratosthenes (who assumed three variables he had not proved: the distance of the Sun, parallel light rays, and that the Earth was spherical) had measured the diameter of the Earth with good precision in the 2nd century BC, and the means of calculating its diameter using an astrolabe was known to both scholars and navigators. Where Columbus differed from the generally accepted view of his time was in his incorrect assumption of a significantly smaller diameter for the Earth, which led him to believe that Asia could be easily reached by sailing west across the Atlantic. Most scholars accepted Ptolemy's correct assessment that the terrestrial landmass (for Europeans of the time, comprising Eurasia and Africa) occupied 180 degrees of the terrestrial sphere, and dismissed Columbus's claim that the Earth was much smaller and that Asia was only a few thousand nautical miles to the west of Europe.

… excerpt ends here. Continue reading the full article.