Mandan and Sacagawea
Mandan village in 1832
Around 1500 AD, Mandan women began to build round houses, or lodges, instead of rectangular ones. They also began to use buffalo skin tipis as tents when they were travelling or hunting. By the 1600s, probably the Mandan were already catching European diseases like measles and smallpox from their Sioux and Mississippian neighbors, even though they hadn't met any Europeans yet. By about 1750, about the same time as the Sioux, the Mandan were able to buy horses from the Apache to their south, which they used to hunt more buffalo than before. It may be that the arrival of the Sioux in the Dakotas once again pushed the Mandan further west, this time on to the Great Plains.
About the same time, the Mandan met Spanish explorers coming from the south-west and French explorers coming from the north-east. The Mandan bought beaver pelts, buffalo hides, and other furs from the Shoshone and Cheyenne to their west and sold them to French and Spanish traders for guns and horses and iron tools and cloth. That's how the Shoshone woman Sacagawea and her husband, the French trader Toussaint Charboneau, came to be living with the Mandan. When Lewis and Clark came by in 1804, the Mandan considered them to be more traders, and the Mandan let Lewis and Clark stay the winter with them, where Lewis and Clark hired Sacagawea and her husband as guides.
Sheheke, the Mandan leader
On their way back, Lewis and Clark brought the Mandan chief, Sheheke, to introduce to the United States President Thomas Jefferson. Sheheke had a good time meeting Jefferson, but it took three years for him to get home, because the Sioux and Arikara people were enemies of the United States and the Mandan and didn't want to let Sheheke through.
In the end, the United States didn't conquer the Mandan, because by the late 1800s, most of the Mandan had already died of smallpox. The few surviving Mandan began to built log cabins, like the Europeans around them, instead of their earth lodges. The United States government took over the Dakotas little by little, gradually taking more and more Mandan land. In 1870, the United States declared 8 million acres of Mandan land to be their reservation. But by 1910, the Mandan reservation was only a tenth as big as it had been in 1870. In 1951, the United States Army built a big hydro-electric dam on the Missouri River that flooded about a quarter of the Mandan reservation, including most of the good farmland. Today, many Mandan operate a casino on their reservation.