European colonization of the Americas significantly impacted native populations from the 15th to 19th centuries. Indigenous groups faced displacement, warfare, enslavement, and diseases brought by Europeans, against which they had no immunity. The Arawak population in Haiti was reduced from 250,000 to just 500 by 1550 due to these factors. Horses introduced by Europeans allowed some tribes to expand their territories but also aided colonizers. Epidemics of diseases like smallpox often immediately followed exploration and destroyed entire villages, with historians estimating up to 80% of some native groups died from European illnesses. The exploration by Europeans marked the beginning of drastic changes to native life in the Americas.