Archaeological study carbon dates existence of one group of Mandan at the Heart River region of what is North Dakota. Another claim they originated near the Gulf of Mexico. They migrate along the Mississippi and Missouri Rivers to the Heart River. Mandan occupy Missouri River Valley from mouth of Bad River in South Dakota to mouth of Knife River in North Dakota. Sahnish oral history traces ancestry to Central America and the Gulf of Mexico.
Sahnish occupy the Bad and Cheyenne River areas. Southern most Mandan move north.
Coronado encounters the Sahnish at the Big Blue River and Mill Creek Valley in Kansas.
Awatixa Hidatsa village group settles at the mouth of the Knife River near the Mandan villages above the Heart River. Archaeological findings support Hidatsa traditional villages at the mouth of the Knife River occupied for a period of residence between 1550 and 1600.
The Mandan villages are situated between the Cannonball and Knife Rivers. The third band of Hidatsa, called Hidatsa Proper, leave their villages in the Devils Lake area and settle in the Missouri River Valley.
The River Crow, called Miro-Kac, separate from the Hidatsa Proper, move west with the introduction of firearms in the Great Lakes area.
Spanish fur trader Le Seur finds Sahnish around the Fort Pierre area. Sahnish occupy 32 villages in the Missouri Trench.
Sahnish living at the Arickara (Grand) River in South Dakota.
Separation of Sahnish and Schirri bands near the Elk Horn River in Nebraska.
Mandan visited by French explorer, Pierre Gaultier De Varennes De La Vérendrye.
La Vérendrye’s son arrives at mouth of Bad River where he meets Chief Little Cherry’s band of Sahnish.
French establish a trading post at the mouth of the Cheyenne River in the Sahnish village.
The Declaration of Independence is drafted by the colonists and the War for Independence begins.
A smallpox epidemic devastates the Mandan at the Heart River village, the Hidatsa at the Knife River villages, and the Awaxawi at the Painted Woods region, and the Sahnish in the Grand River village sites.
Trade and Intercourse Acts passed. First laws to regulate trade with Indian tribes.
Jean Baptiste Trudeau, French fur trader, reports Sahnish still living north of the Arikara (Grand) River.
David Thompson, a Canadian geographer and trader, visits the Mandan villages at the Heart River and the Hidatsa villages at the Knife River.
President Thomas Jefferson commissions Meriwether Lewis and William Clark to explore the Louisiana Territory to open up commerce.
Lewis and Clark spend the winter at the villages of the Mandan and Hidatsa at Knife River.
Sahnish village Chief, Aciita Neesanu (Ankedoucharo) travels to Washington where he dies on April 7, 1806 and is buried at Richmond. His unreported death a year later results in distrust between the Sahnish and the whites.
Shehek Shote (Sheheke) (White Coyote), Mandan Chief of the Mih-Tutta-Hang Kush village, his wife and son, and interpreter Rene Jesseaume travel to Washington to visit President Thomas Jefferson. Sheheke is nicknamed “Big White” by Lewis and Clark.
French trader Alexander Henry visits the Mandan and Hidatsa villages and spends ten days with them.
Shehek Shote (White Coyote), Mandan Chief and family, escorted by a 14-man military escort and some traders attempt return to the Mandan villages but are met by hostile Arikara and Sioux. They return to St. Louis. They are accompanied by a 125-man escort and the American Fur Trade Company and they return to the Mandan villages.
Civilization Fund Act passed—First Indian education program is established.
Lt. Col. Leavenworth sent to punish the Sahnish. He and 700–800 Sioux attack a village—a turning point in Sahnish/white relations. Battle is called the War of 1823. General Henry Atkinson and Major Benjamin O’Fallon are appointed by President James Monroe to arrange treaties with Great Plains tribes, including the Mandan, Hidatsa, and Arikara.
Indian Bureau is created under the War Department.
The United States Government ratifies the Atkinson and O’Fallon Treaty with the Mandan, Hidatsa, and the Arikara. The treaty is designed to secure friendship with the tribes, to control trade with the Indians, and to protect white intruders on Indian lands.
George Catlin arrives at the Mandan and Hidatsa villages at Knife River to make a record of the tribal traditions and customs. He sketches Sahnish people from boat because the Sahnish are too fierce and are feared.
Prince Maximilian of Wied Neuwied and Karl Bodmer visit the Mandan and Hidatsa villages. Bodmer paints the Mandan Chief, Four Bears, and Two Raven of the Dog Society.
Twenty-four Sahnish arrive at the Mandan village. The rest of the band is still in the Black Hills and some are camped on the Knife River. A band of Sahnish is living with the Mandan and the Hidatsa.
The American Fur Company steamboat, St. Peters, docks at Fort Clark. On board was a man afflicted with smallpox. He is taken ashore. Within weeks and the following months, hundreds of Mandan, Hidatsa, and Sahnish, at their various villages, die of the disease.
When the smallpox kills most of their numbers, the remaining Mandan move to the Missouri bottomlands to their winter villages. In their absence, the Sahnish move into their village. The surviving Mandan are joined by the Hidatsa. Maxidivia, Waheenee, Hidatsa oral historian, is born at Knife River.
Father DeSmet visits the villages of the Mandan, Hidatsa, and Sahnish on his way back to St. Louis from a visit with the Flatheads and Nez Perce.
The first trading post in the area is built by James Kipp, and is called Fort James. The name is later changed to Fort Berthold, named after the last prominent fur trading family of St. Louis. Mandan and Hidatsa build Like-A-Fishhook Village led by Hidatsa Chief Four Bears.
Indian Bureau is transferred from the War Department to the Department of Interior.
A delegation travels to Fort Laramie to make a treaty with the tribes on the Great Plains. The Mandan, Hidatsa, and Arikara are accompanied by Father DeSmet, a friend and counselor. The meeting lasts for 18 days. This Fort Laramie Treaty defines the Three Tribes territory consisting of 12,618,301 acres.
Cholera epidemic strikes upper Missouri tribes.
The American Civil War begins. The United States government is preoccupied with the war and ignores its treaty agreements with tribes. March 2, Dakota Territory is created by President James Buchanan. This act opens the way for U.S. Government to build forts in Indian Territory.
The Hidatsa Chief, Four Bears, is killed near Like-A-Fishhook Village by a Sioux raiding party. A few bands of the Sahnish join the Mandan and Hidatsa at Like-A-Fishhook Village, the rest remain across the river because the sacred bundles were to remain on the west side at the Star Village.
Fort Atkinson is absorbed by Fort Berthold, which is then affiliated with the American Fur Company. The Sioux burn abandoned Fort Berthold and the greater villages. The new Fort Berthold, however, is defended.
Washington Matthews, assistant surgeon of the United States Army, is stationed at Fort Stevenson near Fishhook Village and writes Mandan and Hidatsa history and customs.
The American Civil War ends.
July 27, the Mandan, Hidatsa, and Arikara sign the Agreement at Fort Berthold, Dakota Territory.
Bloody Knife, the son of a Sahnish mother and a Sioux father, is employed at Fort Berthold as a mail carrier, and as a scout for General Sully and General Custer.
Mahlon Wilkinson becomes the first government Indian agent to be in Fort Berthold. Colonel DeTrobriand enlists ten Sahnish men, including Bloody Knife, as scouts for the United States Army. Various bands of Sioux, Cheyenne, Arapaho, Crow, Assinaboine, Grose Ventre, Mandan, and Arickara sign the second Fort Laramie Treaty. Present states of Montana, Wyoming, North Dakota, and South Dakota are designated as Indian Territory within the treaty.