Minnesota has been inhabited by various indigenous peoples since the Woodland period of the 11th century BCE. Between roughly 200 and 500 CE, two areas of the indigenous Hopewell tradition emerged: the Laural Complex in the north, and Tremplau Hopewell in the Mississippi River Valley. The subsequent Upper Mississippian culture, consisting of the Oneota people and other Siouan speakers, lasted through the arrival of Europeans in the 17th century. French explorers and missionaries were the earliest Europeans to enter the region, encountering the Dakota, Ojibwe, and various Anishinaabe tribes. Much of what is now Minnesota formed part of the vast French holding of Louisiana, which the United States purchased in 1803. After several subsequent territorial reorganizations, the Minnesota Territory was admitted to the Union in 1858.