The arrival of Europeans in North America had a profound impact on the Aboriginal peoples who had been living here for thousands of years. Virtually everything changed: unfamiliar diseases like smallpox ravished the population; the fur trade and European settlement and resource use decimated the wildlife; new technology such as firearms altered Aboriginal economies and tribal relations; Christian evangelism affected spiritual beliefs and values; European imposition of sovereignty and governmental structures weakened, and in some cases replaced, Aboriginal forms of government; and so on. But more than anything else, the taking of Aboriginal lands by Europeans has probably had the greatest long-term impact on the Aboriginal peoples.