It would have been someone eventually, and unless it would have occurred in some inexplicably modern environment where all the new world populations were immunized to the old world’s diseases and microbiome, it would have been just as deadly.
It happened to have been Columbus, and we know a comparative lot about one of the most important hinge points in the history of humanity. If you think Columbus was a terrible person, you can still appreciate the magnitude of the columbian exchange.
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Imagine Italian food with no tomatoes, no potatoes, no beans, no chocolate, no squash, no corn, or no peppers.
Just what did the Romans eat???