A conquistador is a man who is out to capture a new empire. A conquistador was the title granted to the Fifteenth-to-Seventeenth era. Spanish and Portuguese warriors who captured many of the world, most famously the Central and Southern Americas. Conquistadors were historically significant because they drafted many of the interiors of the New World and gave this information accessible in Europe. But, they also led European conditions into the New World, which was crucial. For example, variola decimated the Local American community.
I believe the answer is smallpox, but I could be mistaken. There were lots of viruses threatening the population at the time but from what I know, smallpox was the largest threat.
