Developmental Implications of Earlier Dates for Early Aztec in the Basin of Mexico

AbstractArchaeologists working in the Basin of Mexico have long accepted a chronology in which sequential ceramic phases (Metepec, Coyotlatelco, Mazapan, Aztec I, and Aztec II) define the period between the last stages of Classic Teotihuacan and the immediate antecedents of Late Postclassic Tenochtitlan. The absolute chronology of these phases has remained tentative, and there have been hints of possible temporal overlap between some of them. A series of 37 new radiocarbon dates from three deep, stratified sites in the Basin of Mexico suggest (1) that the traditional sequence of phases is essentially valid; (2) that both Coyotlatelco and Aztec I may have begun significantly earlier than traditionally believed; (3) that there may have been partial chronological overlap between Late Coyotlatelco and Early Aztec I in some parts of the basin; (4) that there was probably little significant temporal overlap between Aztec I and Aztec II; and (5) that the ethnohistorically recognized sociopolitical complexity of the long era in question is amply reflected in a regional ceramic sequence that still requires considerable refinement in both time and space.