information:filtering, stylistic:tone, stylistic:style_transfer, structural:expansion
Ancient and post-classical history

The pre-Columbian population of the Americas is uncertain; historian David Henige called it "the most unanswerable question in the world." By the end of the 20th century, scholarly consensus favored an estimate of roughly 55 million people, but numbers from various sources have ranged from 10 million to 100 million. Encounters between European explorers and populations in the rest of the world often introduced local epidemics of extraordinary virulence. According to the most extreme scholarly claims, as many as 90% of the Native American population of the New World died of Old World diseases such as smallpox, measles, and influenza. Over the centuries, the Europeans had developed high degrees of immunity to these diseases, while the indigenous peoples had no such immunity.