The Cahokia were an Algonquian-speaking Native American tribe and member of the Illinois Confederation. As a member of the Illinois Confederation, the Cahokia were likely similar to other Illinois groups in culture, economy, and technology. At the time of European contact with the Illini, they were located in what would become the states of Illinois, Iowa, Missouri, and Arkansas. When Europeans first encountered the Cahokia Mounds in southern Illinois they named the site after the Cahokia Tribe which was present in the vicinity but the tribe is not thought to be related to the builders of the Cahokia Mounds. French missionaries built several missions as part of proselytizing efforts of the Cahokia: the Tamaroa/Cahokia mission in 1699 CE and the River L’Abbe mission in 1735 CE. These multiple missions imply the Cahokia was a large enough tribe for the French Seminary of Foreign Missions to justify their construction and operation. The size of the Cahokia decreased in the 18th century likely due to a number of factors, including warfare, disease, and cultural changes, such as Christianization.