When such contexts were not available, we also took samples from construction fills but focused mainly on those containing materials moved from short-period deposits, such as transferred middens and dumps.We developed Bayesian models of our radiocarbon dates by combining information on stratigraphic sequences and ceramic phases.For the Classic Period, we also incorporated calendrical dates.
Despite these similarities in their diachronic trajectories, the outcomes of these collapses were different, with the former associated with the development of dynasties centered on divine rulership and the latter leading to their downfalls.In examining this problematic period, we relied primarily on textual information from inscriptions to identify precise timings of political changes (31, 32).We have reported the results of our chronological study for the Middle Preclassic Period (1000–350 BC) in previous publications (23, 24).Combined with a detailed ceramic sequence, this dataset presents an unprecedented opportunity to examine these critical periods of social change in the Maya area.Ceibal (also spelled Seibal) is the largest site located in the Pasión region of the southwestern Maya lowlands (Fig. The site is known for having one of the earliest ceramic complexes in the Maya lowlands, dating to 1000 BC, and for its late florescence amid the Classic collapse.Ceibal was originally investigated from 1964 through 1968 by the landmark expedition of the Harvard Project (HP) (16–18). Bachand excavated Punta de Chimino as part of the Aguateca Project and obtained 11 radiocarbon assays (19–21).The ceramic chronology established by Sabloff as part of this project provided a solid basis, on which we developed our current study. We began to work at Ceibal as the Ceibal-Petexbatun Archaeological Project (CPAP) in 2005.The Oxcal program version 4.2 facilitated this process through the statistical identification of outliers and visual representations of probability distributions (28, Tables S1 and S2, and Datasets S1 and S2).Our ceramic analysis showed that the original chronology developed by Sabloff was sound and solid.Particularly important moments of political changes in lowland Maya society include the decline of multiple centers at the end of the Preclassic Period (around AD 150–300), the emergence of historically documented dynasties at various centers at the end of the Preclassic Period and during the Early Classic Period (AD 200–600), and the abandonment of many settlements at the end of the Classic Period (around AD 800–950).The Classic collapse has long been an important issue in Maya archaeology (1–6).