Who discovered columbus had found america not India?

The realization that Christopher Columbus had discovered a new continent, rather than reaching India, was largely attributed to Italian explorer Amerigo Vespucci. Through his voyages in the late 1490s and early 1500s, Vespucci provided detailed accounts of the lands he encountered, leading to the conclusion that the territories were part of a separate continent. His name eventually became associated with the New World, as "America" was derived from his first name. This understanding was further solidified by European cartographers and explorers in the following years.