Christopher Columbus (1451 – 1506) (Cristoforo Colombo in Italian, Cristóbal Colón in Spanish, Cristóvão Colombo in Portuguese) was most probably Genoese, although some historians claim he could have been born in other places, from the Crown of Aragó to the Kingdoms of Galicia or Portugal among others. He was an explorer and trader who crossed the Atlantic Ocean and reached the Americas on October 12th 1492 under the flag of Castilian Spain. He believed that the earth was a relatively small sphere, and argued that a ship could reach the Far East via a westward course. 

The somewhat widespread notion that Columbus fought with opposition based on the idea that the earth was flat is a literary myth created by Washington Irving. Contrary to this belief, most people at that time accepted that the earth was round. The main debate was over whether it would be possible to get around the planet without running out of food or getting stuck in windless regions. Although his explorations were not the first to reach the Americas, they inaugurated permanent contact between the New and Old Worlds. 

Columbus was not the first European to reach the continent. Many historians today acknowledge that Vikings had traveled to North America from Greenland in the 11th century and set up a short-lived colony at L'Anse aux Meadows. There is speculation that an obscure Icelandic mariner traveled to the Americas before Columbus and provided him with sources for his claims. There are also many theories of expeditions to the Americas by a variety of peoples throughout time; see Pre-Columbian trans-oceanic contact, one of the most consistent is the first exploration (before 1472) of two, led by João Vaz Corte-Real to Terra Verde (today's Newfoundland). Giovanni Caboto (better known as John Cabot) was first to reach the American mainland (which Columbus did not reach until his third voyage). However, there is one thing that sets off Columbus' first voyage from all of these: less than two decades later, the existence of America was known to the general public throughout Europe. This is likely due to the invention of the printing press. 

Columbus landed in the Bahamas and later explored much of the Caribbean, including the isles of Juana (Cuba) and Espanola (Hispaniola), as well as the coasts of Central and South America. He never reached the present-day United States. "Columbus Day" (12 October, the anniversary of Columbus' landing in the Bahamas) is celebrated as a holiday. 

Unlike the voyage of the Scandinavians, Columbus's voyages led to a relatively quick, general and lasting recognition of the existence of the New World by the Old World, the Columbian Exchange of species (both those harmful to humans, such as viruses, bacteria, and parasites, and beneficial to humans, such as tomatoes, potatoes, maize, and horses), and the first large-scale colonization of the Americas by Europeans. The voyages also inaugurated ongoing commerce between the Old and New Worlds, thus providing the basis for globalization. 

Columbus remains a controversial figure. Some – including many Native Americans – view him as responsible, directly or indirectly, for the deaths of tens, if not hundreds, of millions of indigenous peoples, exploitation of the Americas by Europe, and slavery in the West Indies. Others honor him for the massive boost his explorations gave to Western expansion and culture. Italian Americans hail Columbus as an icon of their heritage. 

It has generally been accepted that he was Genovese, although doubts have persistently been voiced regarding this. His name in Italian is Cristoforo Colombo, in Spanish is Cristóbal Colón, in Catalan it is Cristòfor Colom and in Portuguese Cristóvão Colombo. Columbus is a Latinized form of his surname. The Latin roots of his name can be translated "Christ-bearer, Dove". Columbus' signature reads Xpo ferens ("Bearing Christ"). 

Columbus claimed governorship of the new territories (by prior agreement with the Spanish monarchs) and made several more journeys across the Atlantic. While regarded by some as an excellent navigator, he was seen by many contemporaries as a poor administrator and was stripped of his governorship in 1500.