The Timing of Precolumbian Militarization in the U.S. Midwest and Southeast

Abstract

Bayesian chronological modeling is used to investigate the chronology of bastioned palisades during the precolumbian period in the Midwestern and Southeastern United States. Nine precolumbian settlements in the Midwest and Southeast with bastioned palisades have been subject to scientific dating (Angel Mounds, Annis Village, Aztalan, Cahokia Mounds, Etowah, Kincaid Mounds, Jonathan Creek, Moundville, and Southwind). Complete radiocarbon datasets from these sites are presented within an interpretative Bayesian statistical framework. The results provide a glimpse into the history of Mississippi period (A.D. 1000–1700) fortifications with bastions and indicate that the analyzed fortifications were built and maintained predominantly in A.D. 1200–1400. This finding suggests a greater institutionalized role for defense and warfare in post-A.D. 1200 Mississippian societies. Additionally, modeling results further indicate that the investigated Mississippian centers continued to maintain fortifications for generations after their construction.

Chronology of a Fortified Mississippian Village in the Central Illinois River Valley

“…The estimated use life of the palisade (40-85 yr; 68% probability; Figure 6; Primary Model: Palisade Span) suggests that the structure was standing for at least several decades and, potentially, a century. These results are similar to other Bayesian estimates for the use lives of Mississippian bastioned palisades (Krus 2016;Krus and Cobb 2018), but contrast with previous shorter-use life estimates based on wood decay rates (Bigman et al 2011;Iseminger et al 1990;Scarry 1998). The longer use-life of the Lawrenz palisades suggest that the true use-life of a palisade may only be partially contingent on the durability of its construction materials.…”

“…In contrast, estimates for construction of Cahokia's palisade are cal AD 1245-1315 (68% probability; Figure 7, Cahokia: start palisade; Krus 2016), which is 55-135 yr (68% probability) after Lawrenz (Figure 6; Time-gap between palisade construction at Lawrenz and Cahokia), suggesting a more militarized way of Mississippian life existed at Lawrenz and other northern Mississippian territories and outposts before Cahokia. Krus (2016) shows that the remainder of the 14 C dated bastioned palisades in the midcontinental U.S. were first constructed in the AD 1200s (Figure 7). This coincides with the end of the Medieval Climate Anomaly, which brought decreased summer precipitation (i.e., droughty conditions) that is believed to have caused declines in crop production, increased food scarcity, socio-political instability, and a need for enhanced security (Bird et al 2017;Milner 2007;Milner et al 2013).…”

Contemplating the history and future of radiocarbon dating in the American Southeast

“…We encourage southeastern archaeologists and others working in North America to embrace Bayesian chronological applications given its potential for facilitating a greater understanding of southeastern archaeology, as highlighted by the exponentially growing body of scholarship from the last four years (Anderson et al 2013;Barrier 2017;Cobb et al 2015;Halligan et al 2016;Krus 2016;Krus et al 2015;Moore et al 2017;Munoz et al 2015;Ortmann and Kidder 2013;Pluckhahn et al 2015Pluckhahn et al , 2016Randall 2013;Schilling 2013;Thompson et al 2016;Thulman 2017;Turck and Thompson 2016;Wallis et al 2015;Wright 2014). We especially hope that students will understand the long-term potential that these methods have for transforming our current understandings of chronology in the Southeast.…”

“…We both have created large radiocarbon databases from legacy data and applied them to various projects (e.g., Krus [2016]; Thompson [2014, 2016]). The process of creating these databases relies on cleaning up and evaluating each date, often referred to as radiometric or chronometric hygiene (Bayliss 1999;Faught 2008;Fitzpatrick 2006;Nolan 2011Nolan , 2012Pettitt et al 2003;Spriggs 1989;Spriggs and Anderson 1993;Taché and Hart 2013).…”

“…If we had not known that pine was the primary taxon used for posts, we could have dated a species that did not represent the event we wanted to evaluate (i.e., the construction of structures on the summit). Likewise, Krus (2016) interpreted dated pieces of charred wood deep within Mississippian palisade trenches as termini post quos for the timing of palisade construction and architectural modification, because these samples may have been redeposited from the adjacent ground surface or from older, nearby archaeological features.…”