[In the spirit of Columbus Day, I am re-posting a question that didn't get answered]
At this point, it is a well-known fact that Christopher Columbus was not proving the world was round, nor was he even the first European in America. And even during his own lifetime, it seems (from what I know) that he wasn't accredited as any new "discovery" at all (as he claimed it was Asia, a rather old continent). The first person who said he found a new continent was Amerigo Vespucci, and got the whole thing named after him in c.1507, a year after Columbus died. In Sir Thomas More's book Utopia in 1516, when talking about the "New World" he never mentions Columbus at all, but only talks about Vepucci's discovery. How long did it take before people started treating Columbus as the great "discoverer"? How long did it take before Columbus was elevated to such mythology to outshine Vespucci and all the other explorers of his generation?
In the early XVI century there are already chroniclers crediting Columbus with discovering a new world. For example, Antonio Gallo (1505) and Bartolomeo Senàrega (1514) talk about Columbus in these terms:
Ii etiam affirmaverunt vera esse quae de insulis nuper repertis a Christophoro Columbo Genuensi dicta feruntur. De quo quia in mentionem devenimus, non ingratum forsitan legentibus addere. Nam aetas nostra illi plurimum debet, qui solus aperuit quod ante per tot secula latuit
Translation: It turned out that the information about the islands recently found by Christopher Columbus, Genovese, were true. I mention this because adding it will not be ungrate for the readers. Our age owes him very much, for he alone opened what for all centuries had been hidden.
Martin Waldseemüller, for example, credits Columbus with discovering the Antilles in his famous mapa mundi of 1507. I quote: Iste insule invente sunt per Christophorum Columbum, genuensem, ex mandato regis Castelle (translation: This islands have been discovered by Christopher Columbus, Genoese, on the King of Castile's command).
Christopher Columbus' own son in a very early date (ca. 1506), added a very clear motto to the coat of arms that had been granted to his father in 1493, stating "Por Castilla y por León nuevo mundo halló Colón" (for Castile and for León, a new world found Colón).
However, Amerigo Vespucci was mighty popular in the first years of the XVI century thanks to his own writings, highly embellished though they were, hence why many authors gave Amerigo Vespucci more credit than he was actually due.
Sources:
SENAREGA, Bartolomeo (1514), De rebus genuensibus commentaria. Edition by Emilio Padani (1929)
FERNANDEZ DE OVIEDO, Gonzalo (1535), Historia general y natural de las Indias. Edition by Juan Pérez de Tudela (1959)
FERNANDEZ ARMESTO, Felipe (1992), Cristóbal Colón.
STAGLIENO, Marcello (1888), "Alcuni nuovi documenti intorno a Cristoforo Colombo ed alla sua famiglia", article in Giornale Ligustico, anno XVIII, pages 241-261.