1803. In 1831, government officials vaccinated the Yankton Sioux at Sioux Agency. The Santee Sioux refused vaccination and many died. Depopulation which resulted from European Conquest War and violence While epidemic disease was a leading factor of the population decline of the American Indigenous peoples after 1492, there were other contributing factors, all of them related to European contact and colonization. One of these factors was warfare. According to demographer Russell Thornton, although many people died in wars over the centuries, and war sometimes contributed to the near extinction of certain tribes, warfare and death by other violent means was a comparatively minor cause of overall native population decline. From the U.S. Bureau of the Census in 1894, wars between the government and the Indigenous peoples ranged over 40 in number over the previous 100 years. These wars cost the lives of approximately 19,000 white people, and the lives of about 30,000 Indians, including men, women, and children. They safely estimated that the amount of Native people who were killed or wounded was actually around fifty percent more than what was recorded. There is some disagreement among scholars about how widespread warfare was in pre-Columbian America, but there is general agreement that war became deadlier after the arrival of the Europeans and their firearms. The South or Central American infrastructure allowed for thousands of European conquistadors and tens of thousands of their Indian auxiliaries to attack the dominant Indigenous civilization. Empires such as the Incas depended on a highly centralized administration for the distribution of resources. Disruption caused by the war and the colonization hampered the traditional economy, and possibly led to shortages of food and materials. Across the western hemisphere, war with various Native American civilizations constituted alliances based out of both necessity or economic prosperity and, resulted in mass-scale intertribal warfare. European colonization in the North American continent also contributed to a number of wars between Native Americans, who fought over which of them should have first access to new technology and weaponry—like in the Beaver Wars. Exploitation Some Spaniards objected to the encomienda system of labor, notably Bartolomé de las Casas, who insisted that the Indigenous people were humans with souls and rights. Due to many revolts and military encounters, Emperor Charles V helped relieve the strain on both the native laborers and the Spanish vanguards probing the Caribana for military and diplomatic purposes. Later on New