Native American peoples lived in what is now North Dakota for thousands of years before the coming of Europeans. The known tribes included the Mandan people (from around the 11th century), while the first Hidatsa group arrived a few hundred years later. They both assembled in villages on tributaries of the Missouri River in what would become west-central North Dakota. Crow Indians traveled the plains from the west to visit and trade with the related Hidatsas after the split between them – probably in the 17th century. Later came divisions of the Dakota people – the Lakota, the Santee and the Yanktonai. The Assiniboine and the Plains Cree undertook southward journeys to the village Indians, either for trade or for war. The Shoshone Indians in present-day Wyoming and Montana may have carried out attacks on Indian enemies as far east as the Missouri. A group of Cheyennes lived in a village of earth lodges at the lower Sheyenne River (Biesterfeldt Site) for decades in the 18th century. Due to attacks by Crees, Assiniboines and Chippewas armed with fire weapons, they left the area around 1780 and crossed Missouri some time after. A band of the few Sotaio Indians lived east of Missouri River and met the uprooted Cheyennes before the end of the century. They soon followed the Cheyennes across Missouri and lived among them south of Cannonball River. Eventually, the Cheyenne and the Sutaio became one tribe and turned into mounted buffalo hunters with ranges mainly outside North Dakota. Before the middle of the 19th century, the Arikara entered the future state from the south and joined the Mandan and Hidatsa. With time, a number of Indians entered into treaties with the United States. Many of the treaties defined the territory of a specific tribe (see the map).