Does anybody know anything about the civilisation of Mississippi?

To begin with, there isn't a "civilization of Mississippi" in the sense of a unified political structure throughout the region. When archaeologists talk about the "Mississippians," they're talking about a diverse and widespread collection of peoples spread across a wide region of eastern North America. These various Mississippian cultures had some traits in common, such as adopting similar architectural and artistic styles, the utilization of maize / corn as their staple crop, and a more hierarchical political structure.

Mississippian-style cultures first developed in the Middle Mississippi area (Missouri / Illinois) around 600 CE, not long after the collapse the collapse and fragmentation of the Hopewell cultural sphere (circa 400 CE). The early Emergent Mississippians weren't all that different from the preceding Hopewellian cultures, but two things that set them apart was the shift to maize-based agriculture and the development of more compact settlements. One of these growing villages would eventually grow into the city that archaeologists call "Cahokia."

Between 1000 CE, maize-based agriculture had become widely adopted throughout eastern North America and other post-Hopewellian societies were picking up Mississippian traits.

Around 1050 CE, we see Cahokia become a major power in the Mississippian world. Located across the Mississippi from modern-day St. Louis, it was one of the largest cities in pre-colonial North America (north of Mexico) at its peak. During the Emergent Mississippian period, it probably had a population of less than 3000, but by its peak in 1200s CE, it might have reached a population peak as high as 40,000 (more moderate estimates place it around 20,000). Cahokia was the largest of several Middle Mississippian population centers. It had two close neighbors to its west (located at St. Louis and East St. Louis) that would have been roughly half its size. Two more major centers were located at long the Ohio River - Kincaid Mounds in southern Illinois and Angel Mounds in southern Indiana. With the possible exception of Angel Mounds, there's evidence to suggest that the others were tributaries of Cahokia, or at least on friendly terms with it. In this post, I talk about what likely became of the Cahokians and the other Middle Mississippians as the old Mississippian-styles began to dissolve in this region around 1300 onward.

But Cahokia and the Middle Mississippians weren't the only Mississippians around. Immediately to their south were the Plaquemine Mississippians. While the Middle Mississippians were most likely Dhegihan-speaking peoples, the Plaquemine were likely a mix of Natchezean- and Tunican-speaking peoples. The Natchez themselves are regarded as the last society to retain the definitive Mississippian traits, as their political hierarchy remained intact until 1730. In this post, I talk about Quigualtam, which appears to have been the major Plaquemine power in the mid-1500s.

To the west of the Plaquemine Mississippians were the Caddoan Mississippians. As the name suggests, these would have been Caddoan-speaking peoples living in Oklahoma and neighboring parts of Texas and Kansas. Spiro Mound, in Oklahoma, has long been regarded as the epicenter of Caddoan Mississippian culture, and the art style associated with Spiro had a wide influence over neighboring areas. Spiro had trade contacts with the Pueblos of the Southwest. In the graves at Spiro, we've found cotton from the Southwest and, in one case, an obsidian tool that likely came all the way from the Valley of Mexico. Beside Spiro, the recently rediscovered site of Etzanoa was another major Caddoan Mississippian city. The Spanish visited Etzanoa at least three times between 1541 and 1601, during which time it had a population of about 20,000.

To the east of the Plaquemine Mississippians were the Southeastern / South Appalachian Mississippians, in what's now eastern Mississippi, Alabama, Georgia, and parts of neighboring states. The Southeastern Missisippians were largely Muskogean-speakers, the ancestors of the Creeks, Choctaw, Chickasaw, and Seminoles, among others, though there were also Timucuan-speakers southeast Georgia and northeast Florida. In this series of posts, I discuss two notable examples of the Southeastern Mississippians: Coosa in northern Georgia and Apalachee in northern Florida. Both were visited by the Spanish in the mid-1500s through early 1600s. Of particular note, you'll see how radically different the two polities are. Coosa is spread out of a wide area, with a fairly small capital; while Apalachee is highly compact, with a highly populous capital (estimated by the Spanish to have a population around 30,000 in the early 1600s).

In addition to these "true" Mississippian cultures, there were many Mississippian-adjacent cultures. The erroneously named Fort Ancient culture in Ohio adopted corn and some aspects of Mississippian art and ceremonialism, but didn't pick up their political structures. The Calusa in southern Florida shared some aspects of their political structures and architectural and artistic styles with the Mississippians, but didn't adopt maize-based agriculture.