While returning to Europe in February, 1493 after discovering the New World, Columbus wrote a letter to King Ferdinand and Queen Isabella of Spain, who funded his exploration.
Though the original letter was written in Spanish, a Latin translation was manually printed in several copies. These became the main source of spreading the news of his discovery to the royal courts of Europe and to the papacy.
It is assumed that some time after the authentic eight-page letter became part of the Vatican Library, someone took it out of its binding and replaced it with a forgery, so well done, that no-one noticed. But the US department of homeland security, which discovered that the copy held in the Vatican was fake, contacted Robert Parsons, who had purchased the original letter from a book dealer in 2004, unaware that it had been taken from the Vatican.