[Mikey_1962]

Supposedly Cristobal Colon was from Italy (but there is some thought he was from Barcelona and related to the Colons who were pirates looting the King's ships hense the Italian cover story) so if he was Italian, Spanish was not his first language.

[Publius6961]

Spain is proud of her heritage, and many (not all) of the diaries of the early explorers have been published both in their original form and in modern Spanish.
The only exceptions are documents around the time Spain was finally unified prior to the muslim expulsion. Those libraries remain in the families of the nobles who experienced (and funded) the history.