Relative to the centuries preceding and following it, the tenth century a.d. in Mesoamerica is poorly understood by scholars. Although there is some regional variation in the timing of these events, archaeologists commonly ascribe a pattern of political decline, dynastic collapse, or social reorganization to this period. Paradoxically, increasing interregional interactions and emergent market exchange networks are also characteristics of macroregional patterns during the tenth century. These contradictory phenomena contribute to confusion surrounding interpretations of this transitional time. This article contributes a comparative dataset from systematic archaeological investigations of El Coyote, a monumental center in the lower Cacaulapa valley, Department of Santa Barbara, Honduras. The late occupational phase contains evidence for Early Postclassic chronological markers, including Tohil Plumbate pottery; obsidian from Pachuca, Hidalgo; and copper metallurgy. Calibrated radiocarbon assays with a 2σ error place these contexts between a.d. 710 and 1040, with a clustering of intercepts circa a.d. 900. These results are consistent with a pattern described throughout Mesoamerica and demonstrate that despite variation in the use of cultural terminology—Epiclassic, Terminal Classic, or Early Postclassic—there is uniformity in the timing of this macroregional interaction.

In Mesoamerica, the Early Postclassic (AD 900–1200) is characterized by the long-distance circulation of pottery with a very hard and shiny coating with a metallic aspect, known as Plumbate ware. Plumbate is linked stylistically to the Toltec culture but was produced in workshops in Soconusco (Chiapas). The discovery of a similar collection of sherds during recent work at the site of El Palacio (Zacapu, Michoacán) shows that Plumbate ware also reached this region of Western Mexico. We carried out instrumental neutron activation analyses (INAA) on 11 of the Zacapu fragments and compared the results to the data from ceramic pastes from the region of Soconusco and Pátzcuaro Basin (Michoacán). Ten sherds were produced in Michoacán and are thus a local imitation, whereas the last fragment corresponds to a Tohil-type Plumbate paste and was transported over a long distance. This raises questions of the modalities for the circulation of this pot and the conditions allowing for production of an imitation (transfer of technical know-how?), which we suggest is linked to the Toltec culture in the center of Mexico.

Raised field agriculture in the Basin of Mexico was a highly sustainable farming method that did not depend upon centralised political control. Study of the chinampa system around the Early and Middle Postclassic city of Xaltocan through a combination of remote sensing, GIS, targeted excavation and AMS dating has revealed an extensive area of raised fields that was abandoned when Xaltocan was conquered by an alliance of powerful neighbours during the fourteenth century AD. The rise and abandonment of the chinampa system were thus directly linked to the political economy of the city-state. The failure to revive the raised field systems in the following Aztec period can also be attributed to the impact of political, economic and ecological factors.