The research team will determine the age of building material from monuments and villages in the Eastern and Midwestern U.S. For roughly the last millennium, most people in the Mississippi River Basin began living in villages and towns. The histories of these communities ? the reasons and rate of their development ? are points of scientific debate. Evidence-based explanations for historical change prior to written records is a major contribution of archaeological data, but the science requires accurate and precise dates for objects and events in the past. This project will apply radiocarbon and tree-ring analysis to wood curated in a large museum collection that, due to recent methodological developments, can contribute unique information to questions surrounding the development of complex societies. Both the public and experts have long had an interest in the history of the indigenous societies of the Mississippi River Basin, particularly the construction of the large pyramid mounds at the center of ancient towns in the region. This study will contribute the most precise calendar dates ever obtained for the construction for some of these monuments, and the data will aid research on the importance of population change and the use of monuments to structure social and political relationships in the past. The systematic application of tree-ring based methods significantly improves knowledge on the timing of past events and enables theoretical advances in archaeology. This study will apply these techniques on a large scale in the Eastern and Midwestern U.S. and will generate high precision calendar dates for the timing and tempo of monument construction, the duration of village occupation, and the spread of culture attributes characteristic of ?Mississippian? society. The size of the tree ring collection and the diversity of contexts mean that the results would represent a major improvement in the precision of Mississippian culture history. This will contribute significantly to archaeology in the region and help extend millennial length tree-ring chronologies. Overall, our results will contribute to the goal of developing event-based histories of monumentality and culture change in emergent complex societies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.