The story of the pre-Columbian Mississippi Period (1000 ce–1600 ce) of the American South and parts of the Midwest is the story of the rise of the ancient Mississippian towns and cities and the world they made, the history of that world, and its collapse with European contact. First, however, readers must become acquainted with the chiefdom concept as it applies to these ancient towns and cities in order to outline some of the basic organizing structures of Mississippian political units. The Mississippi Period began with the rise of the great Indian city of Cahokia and the long reach of its influence over a vast region, resulting in a new social, religious, and political ordering across the land and the formation of numerous polities that archaeologists call “chiefdoms” (the Early Mississippi Period 1000 ce–1300 ce). The fall of Cahokia around 1300 ce cleared the way for the elaboration of these early chiefdoms and the rise of others throughout the Mississippian world (the Middle Mississippi Period 1300–1475 ce). Many of these grand Middle Mississippi chiefdoms, in turn, collapsed around 1450 ce. In the wake of this collapse, people regrouped and built new chiefdoms throughout the American South (the Late Mississippi Period 1475–1600 ce). These are the people that the early Spanish explorers met in the 16th century. Encounters with the Spaniards set in motion a series of colonial disruptions of warfare, disease, and commercial slave raiding that resulted in another collapse of the Mississippian world, only this time never to rise again. However, the survivors of these fallen chiefdoms regrouped and restructured their lives and societies for living in a new world order—this one being a colonial world on the margins of an expanding European empire.