Christopher Columbus

Christopher Columbus was born between the 25th of August and the 31st of October 1451 in the Republic of Genoa, the son of a wool weaver named Domenico and a mother named Susanna Fontanarossa. He began working in his father's cheese stand and tavern at a young age, but his destiny lay not in the fields of Liguria but on the open ocean. By the time he was 14, he had already taken to the sea, traveling as far north as the British Isles and as far south as the coast of modern-day Ghana. His early life was marked by a series of voyages that took him from the Mediterranean to the Atlantic, including a shipwreck off the coast of Portugal in 1476 that left him stranded in Lagos. He eventually made his way to Lisbon, where he lived for several years and married Filipa Moniz Perestrelo, a Portuguese noblewoman. This marriage connected him to the Portuguese maritime elite and provided him with access to the nautical charts and logs of her deceased father, which would later prove crucial to his understanding of Atlantic navigation. Columbus was largely self-educated, reading widely in geography, astronomy, and history, and he developed a plan to seek a western sea passage to the East Indies, hoping to profit from the lucrative spice trade. His journey from a Genoese weaver to a Spanish admiral was driven by a combination of ambition, religious conviction, and a profound misunderstanding of the size of the Earth.

The Mathematics of Error

Columbus's plan to reach Asia by sailing west was based on a series of calculations that were fundamentally flawed, yet they were the only ones that made his voyage seem feasible to the Catholic Monarchs. He believed the Earth was much smaller than it actually was, estimating the distance from the Canary Islands to Japan to be only 2,400 nautical miles, when the actual distance was closer to 10,000 nautical miles. This error stemmed from his reliance on the work of Ptolemy, who had used smaller units of distance, and his acceptance of the idea that the Eurasian landmass extended much further east than it actually did. Columbus also believed that there were inhabited islands, such as the mythical Antillia, that would break up the journey and provide stopping points. He was influenced by the writings of Marco Polo, who claimed that Japan was some distance to the east of China, and by the ideas of the Florentine astronomer Paolo dal Pozzo Toscanelli, who suggested that a westward route to Asia was possible. Despite these errors, Columbus's plan held the promise of a competitive edge for Spain in the quest for trade with the Indies, and it was this promise that eventually convinced Queen Isabella and King Ferdinand to sponsor his voyage. The mathematical miscalculations that nearly doomed his expedition were the very same ones that made it seem like a viable option to the Spanish Crown.

Common questions

When and where was Christopher Columbus born?

Christopher Columbus was born between the 25th of August and the 31st of October 1451 in the Republic of Genoa. He was the son of a wool weaver named Domenico and a mother named Susanna Fontanarossa.

What were the specific dates of Christopher Columbus's first voyage to the Americas?

Christopher Columbus departed from Palos de la Frontera on the 3rd of August 1492 and landed on an island he named San Salvador on the 12th of October 1492. This voyage marked the first recorded landing of Europeans on the mainland of South America when he later reached Venezuela on the 5th of August 1498.

How did Christopher Columbus die and what medical condition might he have had?

Christopher Columbus died in Valladolid on the 20th of May 1506 at the age of 54 after suffering from prolonged attacks of gout and other fevers. Modern medical analysis suggests he may have suffered from reactive arthritis caused by intestinal bacterial infections or sexually transmitted diseases.

Where are the remains of Christopher Columbus located today?

The remains of Christopher Columbus were moved to the Seville Cathedral in Spain after being exhumed from Santo Domingo in 1536. Some remains were also moved to Havana, Cuba in 1793 and later returned to Seville, while other remains remain in the Columbus Lighthouse in Santo Domingo Este.

Why did Christopher Columbus believe the Earth was smaller than it actually is?

Christopher Columbus believed the Earth was smaller than it actually was because he relied on the work of Ptolemy who used smaller units of distance and accepted the idea that the Eurasian landmass extended much further east. He estimated the distance from the Canary Islands to Japan to be only 2,400 nautical miles when the actual distance was closer to 10,000 nautical miles.

What was the outcome of Christopher Columbus's fourth voyage to the Americas?

Christopher Columbus's fourth voyage ended with his ships being beached in Saint Ann Parish, Jamaica on the 25th of June 1503 where he and 230 of his men remained stranded for six months. He and his men were finally rescued on the 28th of June 1504 and arrived in Sanlúcar, Spain on the 7th of November 1504.

The Second Voyage and the Slave Raid

On the 24th of September 1493, Columbus sailed from Cádiz with 17 ships and nearly 1,500 men, including sailors, soldiers, priests, carpenters, stonemasons, metalworkers, and farmers. The fleet stopped at the Canary Islands to take on more supplies, and set sail again on the 7th of October, deliberately taking a more southerly course than on the first voyage. On the 17th of November, Columbus first sighted the eastern coast of the island of Puerto Rico, known to its native Taino people as Boriquén. His fleet sailed along the island's southern coast for a whole day, before making landfall on its northwestern coast at the Bay of Añasco, early on the 19th of November. Upon landing, Columbus christened the island San Juan Bautista after John the Baptist, and remained anchored there for two days from the 20th to the 21st of November, filling the water casks of the ships in his fleet. On the 22nd of November, Columbus returned to Hispaniola to visit La Navidad, where 39 Spaniards had been left during the first voyage. He found the fort in ruins and learned from Guacanagaríx, the local tribe leader, that his men had quarreled over gold and taken women from the tribe, and that after some left for the territory of Caonabo, Caonabo came and burned the fort and killed the rest of the men there. Columbus then established a poorly located and short-lived settlement to the east, La Isabela, in the present-day Dominican Republic. By the end of 1494, disease and famine had killed two-thirds of the Spanish settlers there. From April to August 1494, Columbus explored Cuba and Jamaica, then returned to Hispaniola. Before leaving on this exploration to Cuba, Columbus had ordered a large number of men, under Pedro Margarit, to journey the length and breadth of the island, enforcing Spanish control and bringing all the people under the Spanish yoke. These men, in his absence, raped women, took men captive to be servants, and stole from the indigenous people. A number of Spanish were killed in retaliation. By the time Columbus returned from exploring Cuba, the four primary leaders of the Arawak people in Hispaniola were gathering for war to try to drive the Spanish from the Island. Columbus assembled a large number of troops, and joined with his one native ally, chief Guacanagaríx, met for battle. The Spanish, even though they were largely outnumbered, won this battle, and over the next 9 months Columbus continued to wage war on the native Taíno on Hispaniola until they surrendered and agreed to pay tribute. Columbus implemented the encomienda, a Spanish labor system that rewarded conquerors with the labor of conquered non-Christian people. It is also recorded that punishments to both Spaniards and natives included whippings and mutilation, such as cutting noses and ears. Columbus and the colonists enslaved many of the indigenous people, including children. Natives were beaten, raped, and tortured for the location of imagined gold. Thousands committed suicide rather than face the oppression. In February 1495, Columbus rounded up about 1,500 Arawaks, some of whom had rebelled, in a great slave raid. About 500 of the strongest were shipped to Spain as slaves, with about two hundred of those dying en route. In June 1495, the Spanish Crown sent ships and supplies to Hispaniola. In October, Florentine merchant Gianotto Berardi, who had won the contract to provision the fleet of Columbus's second voyage and to supply the colony on Hispaniola, received almost 40,000 worth of enslaved Indians. He renewed his effort to get supplies to Columbus, and was working to organize a fleet when he suddenly died in December. On the 10th of March 1496, having been away about 30 months, the fleet departed La Isabela. On the 8th of June the crew sighted land somewhere between Lisbon and Cape St. Vincent, and disembarked in Cádiz on the 11th of June.

The Chains of Santo Domingo

On the 30th of May 1498, Columbus left with six ships from Sanlúcar, Spain. The fleet called at Madeira and the Canary Islands, where it divided in two, with three ships heading for Hispaniola and the other three vessels, commanded by Columbus, sailing south to the Cape Verde Islands and then westward across the Atlantic. It is probable that this expedition was intended at least partly to confirm rumors of a large continent south of the Caribbean Sea, that is, South America. On the 31st of July they sighted Trinidad, the most southerly of the Caribbean islands. On the 5th of August, Columbus sent several small boats ashore on the southern side of the Paria Peninsula in what is now Venezuela, near the mouth of the Orinoco river. This was the first recorded landing of Europeans on the mainland of South America, which Columbus realized must be a continent. The fleet then sailed to the islands of Chacachacare and Margarita, reaching the latter on the 14th of August, and sighted Tobago and Grenada from afar, according to some scholars. On the 19th of August, Columbus returned to Hispaniola. There he found settlers in rebellion against his rule, and his unfulfilled promises of riches. Columbus had some of the Europeans tried for their disobedience; at least one rebel leader was hanged. In October 1499, Columbus sent two ships to Spain, asking the Court of Spain to appoint a royal commissioner to help him govern. By this time, accusations of tyranny and incompetence on the part of Columbus had also reached the Court. The sovereigns sent Francisco de Bobadilla, a relative of Marquesa Beatriz de Bobadilla, a patron of Columbus and a close friend of Queen Isabella, to investigate the accusations of brutality made against the Admiral. Arriving in Santo Domingo while Columbus was away, Bobadilla was immediately met with complaints about all three Columbus brothers. He moved into Columbus's house and seized his property, took depositions from the Admiral's enemies, and declared himself governor. Bobadilla reported to Spain that Columbus once punished a man found guilty of stealing corn by having his ears and nose cut off and then selling him into slavery. He claimed that Columbus regularly used torture and mutilation to govern Hispaniola. Testimony recorded in the report stated that Columbus congratulated his brother Bartholomew on defending the family when the latter ordered for a woman to be paraded naked through the streets and then had her tongue cut because she had spoken ill of the admiral and his brothers. The document also describes how Columbus put down native unrest and revolt: he first ordered a brutal suppression of the uprising in which many natives were killed, and then paraded their dismembered bodies through the streets in an attempt to discourage further rebellion. Columbus vehemently denied the charges. The neutrality and accuracy of the accusations and investigations of Bobadilla toward Columbus and his brothers have been disputed by historians, given the anti-Italian sentiment of the Spaniards and Bobadilla's desire to take over Columbus's position. In early October 1500, Columbus and Diego presented themselves to Bobadilla, and were put in chains aboard La Gorda, the caravel on which Bobadilla had arrived at Santo Domingo. They were returned to Spain, and languished in jail for six weeks before King Ferdinand ordered their release. Not long after, the king and queen summoned the Columbus brothers to the Alhambra palace in Granada. The sovereigns expressed indignation at the actions of Bobadilla, who was then recalled and ordered to make restitutions of the property he had confiscated from Columbus. The royal couple heard the brothers' pleas; restored their freedom and wealth; and, after much persuasion, agreed to fund Columbus's fourth voyage. However, Nicolás de Ovando was to replace Bobadilla and be the new governor of the West Indies.

The Fourth Voyage and the Stranded Men

On the 9th of May 1502, Columbus left Cádiz with his flagship Santa María and three other vessels. The ships were crewed by 140 men, including his brother Bartholomew as second in command and his son Fernando. He sailed to Asilah on the Moroccan coast to rescue Portuguese soldiers said to be besieged by the Moors. The siege had been lifted by the time they arrived, so the Spaniards stayed only a day and continued on to the Canary Islands. On the 15th of June, the fleet arrived at Martinique, where it lingered for several days. A hurricane was forming, so Columbus continued westward, hoping to find shelter on Hispaniola. He arrived at Santo Domingo on the 29th of June, but was denied port, and the new governor Francisco de Bobadilla refused to listen to his warning that a hurricane was approaching. Instead, while Columbus's ships sheltered at the mouth of the Rio Jaina, the first Spanish treasure fleet sailed into the hurricane. Columbus's ships survived with only minor damage, while 20 of the 30 ships in the governor's fleet were lost along with 500 lives, including that of Francisco de Bobadilla. Although a few surviving ships managed to straggle back to Santo Domingo, the fragile ship carrying Columbus's personal belongings and his 4,000 pesos in gold was the sole vessel to reach Spain. The gold was his tenth of the profits from Hispaniola, equal to 240,000 maravedis, guaranteed by the Catholic Monarchs in 1492. After a brief stop at Jamaica, Columbus sailed to Central America, arriving at the coast of Honduras on the 30th of July. Here Bartholomew found native merchants and a large canoe. On the 14th of August, Columbus landed on the continental mainland at Punta Caxinas, now Puerto Castilla, Honduras. He spent two months exploring the coasts of Honduras, Nicaragua, and Costa Rica, seeking a strait in the western Caribbean through which he could sail to the Indian Ocean. Sailing south along the Nicaraguan coast, he found a channel that led into Almirante Bay in Panama on the 5th of October. As soon as his ships anchored in Almirante Bay, Columbus encountered Ngäbe people in canoes who were wearing gold ornaments. In January 1503, he established a garrison at the mouth of the Belén River. Columbus left for Hispaniola on the 16th of April. On the 10th of May he sighted the Cayman Islands, naming them after the numerous sea turtles there. His ships sustained damage in a storm off the coast of Cuba. Unable to travel farther, on the 25th of June 1503 they were beached in Saint Ann Parish, Jamaica. For six months Columbus and 230 of his men remained stranded on Jamaica. Diego Méndez de Segura, who had shipped out as a personal secretary to Columbus, and a Spanish shipmate called Bartolomé Flisco, along with six natives, paddled a canoe to get help from Hispaniola. The governor, Nicolás de Ovando y Cáceres, detested Columbus and obstructed all efforts to rescue him and his men. In the meantime Columbus, in a desperate effort to induce the natives to continue provisioning him and his hungry men, won their favor by predicting a lunar eclipse for the 29th of February 1504, using Abraham Zacuto's astronomical charts. Despite the governor's obstruction, Christopher Columbus and his men were rescued on the 28th of June 1504, and arrived in Sanlúcar, Spain, on the 7th of November.

The Final Years and the Death of an Admiral

Columbus had always claimed that the conversion of non-believers was one reason for his explorations, and he grew increasingly religious in his later years. Probably with the assistance of his son Diego and his friend the Carthusian monk Gaspar Gorricio, Columbus produced two books during his later years: a Book of Privileges, detailing and documenting the rewards from the Spanish Crown to which he believed he and his heirs were entitled, and a Book of Prophecies, in which passages from the Bible were used to place his achievements as an explorer in the context of Christian eschatology. In his later years, Columbus demanded that the Crown of Castile give him his tenth of all the riches and trade goods yielded by the new lands, as stipulated in the Capitulations of Santa Fe. Because he had been relieved of his duties as governor, the Crown did not feel bound by that contract and his demands were rejected. After his death, his heirs sued the Crown for a part of the profits from trade with America, as well as other rewards. This led to a protracted series of legal disputes known as the Columbian lawsuits. During a violent storm on his first return voyage, Columbus, then 41, had suffered an attack of what was believed at the time to be gout. In subsequent years, he was plagued with what was thought to be influenza and other fevers, bleeding from the eyes, temporary blindness and prolonged attacks of gout. The attacks increased in duration and severity, sometimes leaving Columbus bedridden for months at a time, and culminated in his death 14 years later. Based on Columbus's lifestyle and the described symptoms, some modern commentators suspect that he suffered from reactive arthritis, rather than gout. Reactive arthritis is a joint inflammation caused by intestinal bacterial infections or after acquiring certain sexually transmitted diseases, primarily chlamydia or gonorrhea. In 2006, Frank C. Arnett, a medical doctor, and historian Charles Merrill, published their paper in The American Journal of the Medical Sciences proposing that Columbus had a form of reactive arthritis; Merrill made the case in that same paper that Columbus was the son of Catalans and his mother possibly a member of a prominent converted Jewish family. It seems likely that he acquired reactive arthritis from food poisoning on one of his ocean voyages because of poor sanitation and improper food preparation, says Arnett, a rheumatologist and professor of internal medicine, pathology and laboratory medicine at the University of Texas Medical School at Houston. Some historians such as H. Micheal Tarver and Emily Slape, as well as medical doctors such as Arnett and Antonio Rodríguez Cuartero, believe that Columbus had such a form of reactive arthritis, but according to other authorities, this is speculative, or very speculative. After his arrival to Sanlúcar from his fourth voyage and Queen Isabella's death, an ill Columbus settled in Seville in April 1505. He stubbornly continued to make pleas to the Crown to defend his own personal privileges and his family's. He moved to Segovia where the court was at the time on a mule by early 1506, and, on the occasion of the wedding of King Ferdinand with Germaine of Foix in Valladolid, Spain, in March 1506, Columbus moved to that city to persist with his demands. On the 20th of May 1506, aged 54, Columbus died in Valladolid.

The Shifting Legacy of a Controversial Figure

Columbus's remains were first buried at the Chapel of Wonders at the Convent of St. Francis, Valladolid, but were then moved to the monastery of La Cartuja in Seville by the will of his son Diego. They may have been exhumed in 1513 and interred at the Seville Cathedral. In about 1536, the remains of both Columbus and his son Diego were moved to a cathedral in Colonial Santo Domingo, in the present-day Dominican Republic; Columbus had requested to be buried on the island. By some accounts, in 1793, when France took over the entire island of Hispaniola, Columbus's remains were moved to Havana, Cuba. Captain George Farquar of Lord Stanley brought the news to Liverpool in 1796 that while he had been at Havana, the Spanish ship of the line had arrived there carrying the coffin, bones and fetters of Christopher Columbus from San Domingo to be re-interred at Havana with the highest military honours. After Cuba became independent following the Spanish-American War in 1898, at least some of these remains were moved back to the Seville Cathedral, where they were placed on an elaborate catafalque. In June 2003, DNA samples were taken from the remains in Seville, as well as those of Columbus's brother Diego and younger son Fernando. Initial observations suggested that the bones did not appear to match Columbus's physique or age at death. DNA extraction proved difficult; only short fragments of mitochondrial DNA could be isolated. These matched corresponding DNA from Columbus's brother, supporting that the two men had the same mother. Such evidence, together with anthropologic and historic analyses, led the researchers to conclude that the remains belonged to Christopher Columbus. In 1877, a priest discovered a lead box at Santo Domingo inscribed: Discoverer of America, First Admiral. Inscriptions found the next year read Last of the remains of the first admiral, Sire Christopher Columbus, discoverer. The box contained bones of an arm and a leg, as well as a bullet. These remains were considered legitimate by physician and U.S. Assistant Secretary of State John Eugene Osborne, who suggested in 1913 that they travel through the Panama Canal as a part of its opening ceremony. These remains were kept at the Basilica Cathedral of Santa María la Menor in the Colonial City of Santo Domingo before being moved to the Columbus Lighthouse in Santo Domingo Este, inaugurated in 1992. The authorities in Santo Domingo have never allowed these remains to be DNA-tested, so it is unconfirmed whether they are from Columbus's body as well. The figure of Columbus was not ignored in the British colonies during the colonial era: Columbus became a unifying symbol early in the history of the colonies that became the United States when Puritan preachers began to use his life story as a model for a developing American spirit. In the spring of 1692, Puritan preacher Cotton Mather described Columbus's voyage as one of three shaping events of the modern age, connecting Columbus's voyage and the Puritans' migration to North America, seeing them together as the key to a grand design. The use of Columbus as a founding figure of New World nations spread rapidly after the American Revolution. This was out of a desire to develop a national history and founding myth with fewer ties to Britain. His name was the basis for the female national personification of the United States, Columbia, in use since the 1730s with reference to the original Thirteen Colonies, and also a historical name applied to the Americas and to the New World. Columbia, South Carolina, and Columbia Rediviva, the ship for which the Columbia River was named, are named for Columbus. Columbus's name was given to the newly born Republic of Colombia in the early 19th century, inspired by the political project of Colombeia developed by revolutionary Francisco de Miranda, which was put at the service of the emancipation of continental Hispanic America. To commemorate the 400th anniversary of the landing of Columbus, the 1893 World's Fair in Chicago was named the World's Columbian Exposition. The U.S. Postal Service issued the first U.S. commemorative stamps, the Columbian Issue, depicting Columbus, Queen Isabella and others in various stages of his several voyages. A commemorative silver half dollar was also struck, which remains the only U.S. currency issued having a foreigner as its subject. The policies related to the celebration of the Spanish colonial empire as the vehicle of a nationalist project undertaken in Spain during the Restoration in the late 19th century took form with the commemoration of the 4th centenary on the 12th of October 1892 in which the figure of Columbus was extolled by the Conservative government, eventually becoming the very same national day. Several monuments commemorating the discovery were erected in cities such as Palos, Barcelona, Granada, Madrid, Salamanca, Valladolid and Seville in the years around the 400th anniversary. For the Columbus Quincentenary in 1992, a second Columbian issue was released jointly with Italy, Portugal, and Spain. Columbus was celebrated at Seville Expo 92, and Genoa Expo 92. The Boal Mansion Museum, founded in 1951, contains a collection of materials concerning later descendants of Columbus and collateral branches of the family. It features a 16th-century chapel from a Spanish castle reputedly owned by Diego Colón which became the residence of Columbus's descendants. The chapel interior was dismantled and moved from Spain in 1909 and re-erected on the Boal estate at Boalsburg, Pennsylvania. Inside it are numerous religious paintings and other objects including a reliquary with fragments of wood supposedly from the True Cross. The museum also holds a collection of documents mostly relating to Columbus descendants of the late 18th and 19th centuries. In many countries of the Americas, as well as Spain and Italy, Columbus Day celebrates the anniversary of Columbus's arrival in the Americas on the 12th of October 1492. The voyages of Columbus are considered a turning point in human history, marking the beginning of globalization and accompanying demographic, commercial, economic, social, and political changes. The landing of Columbus became a powerful icon of American genesis in the 19th century. His explorations resulted in permanent contact between the two hemispheres, and the term pre-Columbian is used to refer to the cultures of the Americas before the arrival of Columbus and his European successors. The ensuing Columbian exchange saw the massive exchange of animals, plants, fungi, diseases, technologies, mineral wealth and ideas. In the first century after his endeavors, Columbus's figure largely languished in the backwaters of history, and his reputation was beset by his failures as a colonial administrator. His legacy was somewhat rescued from oblivion when he began to appear as a character in Italian and Spanish plays and poems from the late 16th century onward. Columbus was subsumed into the Western narrative of colonization and empire building, which invoked notions of translatio imperii and translatio studii to underline who was considered civilized and who was not. The Americanization of the figure of Columbus began in the latter decades of the 18th century, after the revolutionary period of the United States, elevating the status of his reputation to a national myth, homo americanus. His landing became a powerful icon as an image of American genesis. The Discovery of America sculpture, depicting Columbus and a cowering Native maiden, was commissioned on the 3rd of April 1837, when U.S. President Martin Van Buren sanctioned the engineering of Luigi Persico's design. This representation of Columbus's triumph and the Native's recoil is a demonstration of supposed white superiority over savage, naive Natives. As recorded during its unveiling in 1844, the sculpture extends to represent the meeting of the two races, as Persico captures their first interaction, highlighting the moral and intellectual inferiority of Natives. Placed outside the U.S. Capitol building where it remained until its removal in the mid-20th century, the sculpture reflected the contemporary view of whites in the U.S. toward the Natives; they are labeled merciless Indian savages in the United States Declaration of Independence. In 1836, Pennsylvania senator and future U.S. President James Buchanan, who proposed the sculpture, described it as representing the great discoverer when he first bounded with ecstasy upon the shore, ail his toils past, presenting a hemisphere to the astonished world, with the name America inscribed upon it. Whilst he is thus standing upon the shore, a female savage, with awe and wonder depicted in his countenance, is gazing upon him. The American Columbus myth was reconfigured later in the century when he was enlisted as an ethnic hero by immigrants to the United States who were not of Anglo-Saxon stock, such as Jewish, Italian, and Irish people, who claimed Columbus as a sort of ethnic founding father. Catholics unsuccessfully tried to promote him for canonization in the 19th century. From the 1990s onward, a narrative of Columbus being responsible for the genocide of indigenous peoples and environmental destruction began to compete with the then predominant discourse of Columbus as Christ-bearer, scientist, or father of America. This narrative features the negative effects of Columbus' conquests on native populations. Exposed to Old World diseases, the indigenous populations of the New World collapsed, and were largely replaced by Europeans and Africans, who brought with them new methods of farming, business, governance, and religious worship. Though Christopher Columbus came to be considered the European discoverer of America in Western popular culture, his historical legacy is more nuanced. After settling Iceland, the Norse settled the uninhabited southern part of Greenland beginning in the 10th century. Norsemen are believed to have then set sail from Greenland and Iceland to become the first known Europeans to reach the North American mainland, nearly 500 years before Columbus reached the Caribbean. The 1960s discovery of a Norse settlement dating c. 1000 at L'Anse aux Meadows, Newfoundland, partially corroborates accounts within the Icelandic sagas of Erik the Red's colonization of Greenland and his son Leif Erikson's subsequent exploration of a place he called Vinland. In the 19th century, amid a revival of interest in Norse culture, Carl Christian Rafn and Benjamin Franklin DeCosta wrote works establishing that the Norse had preceded Columbus in colonizing the Americas. Following this, in 1874 Rasmus Bjørn Anderson argued that Columbus must have known of the North American continent before he started his voyage of discovery. Most modern scholars doubt Columbus had knowledge of the Norse settlements in America, with his arrival to the continent being most likely an independent discovery. Europeans devised explanations for the origins of the Native Americans and their geographical distribution with narratives that often served to reinforce their own preconceptions built on ancient intellectual foundations. In modern Latin America, the non-Native populations of some countries often demonstrate an ambiguous attitude toward the perspectives of indigenous peoples regarding the so-called discovery by Columbus and the era of colonialism that followed. In his 1960 monograph, Mexican philosopher and historian Edmundo O'Gorman explicitly rejects the Columbus discovery myth, arguing that the idea that Columbus discovered America was a misleading legend fixed in the public mind through the works of American author Washington Irving during the 19th century. O'Gorman argues that to assert Columbus discovered America is to shape the facts concerning the events of 1492 to make them conform to an interpretation that arose many years later. For him, the Eurocentric view of the discovery of America sustains systems of domination in ways that favor Europeans. In a 1992 article for The UNESCO Courier, Félix Fernández-Shaw argues that the word discovery prioritizes European explorers as the heroes of the contact between the Old and New World. He suggests that the word encounter is more appropriate, being a more universal term which includes Native Americans in the narrative. Historians have traditionally argued that Columbus remained convinced until his death that his journeys had been along the east coast of Asia as he originally intended, excluding arguments such as Anderson's. On his third voyage he briefly referred to South America as a hitherto unknown continent, while also rationalizing that it was the Earthly Paradise Eden located at the end of the Orient. Columbus continued to claim in his later writings that he had reached Asia; in a 1502 letter to Pope Alexander VI, he asserts that Cuba is the east coast of Asia. On the other hand, in a document in the Book of Privileges, 1502, Columbus refers to the New World as the Indias Occidentales, which he says were unknown to all the world. Washington Irving's 1828 biography of Columbus popularized the idea that Columbus had difficulty obtaining support for his plan because nearly all educated Westerners of Columbus's time knew that the Earth is spherical, a concept that had been understood since antiquity. The techniques of celestial navigation, which uses the position of the Sun and the stars in the sky, had long been in use by astronomers and were beginning to be implemented by mariners. However, Columbus made several errors in calculating the size of the Earth, the distance the continent extended to the east, and therefore the distance to the west to reach his goal. First, as far back as the 3rd century BC, Eratosthenes had correctly computed the circumference of the Earth by using simple geometry and studying the shadows cast by objects at two remote locations. In the 1st century BC, Posidonius confirmed Eratosthenes's results by comparing stellar observations at two separate locations. These measurements were widely known among scholars, but Ptolemy's use of the smaller, old-fashioned units of distance led Columbus to underestimate the size of the Earth by about a third. Second, three cosmographical parameters determined the bounds of Columbus's enterprise: the distance across the ocean between Europe and Asia, which depended on the extent of the oikumene, i.e., the Eurasian land-mass stretching east-west between Spain and China; the circumference of the Earth; and the number of miles or leagues in a degree of longitude, which was possible to deduce from the theory of the relationship between the size of the surfaces of water and the land as held by the followers of Aristotle in medieval times. From Pierre d'Ailly's, Columbus learned of Alfraganus's estimate that a degree of latitude equal to approximately a degree of longitude along the equator spanned 56.67 Arabic miles equivalent to or 76.2 mi, but he did not realize that this was expressed in the Arabic mile about 1,850 m rather than the shorter Roman mile about 1,480 m with which he was familiar. Columbus therefore estimated the size of the Earth to be about 75% of Eratosthenes's calculation. Third, most scholars of the time accepted Ptolemy's estimate that Eurasia spanned 180° longitude, rather than the actual 130° to the Chinese mainland or 150° to Japan at the latitude of Spain. Columbus believed an even higher estimate, leaving a smaller percentage for water. In d'Ailly's, Columbus read Marinus of Tyre's estimate that the longitudinal span of Eurasia was 225° at the latitude of Rhodes. Some historians, such as Samuel Eliot Morison, have suggested that he followed the statement in the apocryphal book 2 Esdras 6:42 that six parts of the globe are habitable and the seventh is covered with water. He was also aware of Marco Polo's claim that Japan which he called Cipangu was some distance to the east of China Cathay, and closer to the equator than it is. He was influenced by Toscanelli's idea that there were inhabited islands even farther to the east than Japan, including the mythical Antillia, which he thought might lie not much farther to the west than the Azores, and the distance westward from the Canary Islands to the Indies as only 68 degrees, equivalent to a 58% error. Based on his sources, Columbus estimated a distance of 2,400 nautical miles from the Canary Islands west to Japan; the actual distance is 10,000 nautical miles. No ship in the 15th century could have carried enough food and fresh water for such a long voyage, and the dangers involved in navigating through the uncharted ocean would have been formidable. Most European navigators reasonably concluded that a westward voyage from Europe to Asia was unfeasible. The Catholic Monarchs, however, having completed the Granada War, an expensive war against the Moors in the Iberian Peninsula, were eager to obtain a competitive edge over other European countries in the quest for trade with the Indies. Columbus's project, though far-fetched, held the promise of such an advantage.