1962, 1965a, 1965b). One of the problems in the archaeology of the northern lowlands has always been the lack of sites with extended periods of occupation, which has led in part to the confusion about the cultural stratigraphy and regional chronology. Dzibilchaltún has the advantage of continuous occupation over a long archaeological sequence, which according to Andrews not only confirms the Pure Florescent-Modified Florescent-Decadent period sequence, but also indicates the Puuc or Pure Florescent sites of the northern lowlands are later than and not contemporary with the Tepeu 2 ceramic phase in the southern lowlands. Andrews defended his observations concerning the stratigraphic position of the Puuc sites in relation to the Late Classic southern centers until the end of his life, and his work is supported by other Tulane archaeologists and by ceramic testing from Uxmal and Kabah (Andrews IV 1973; Ball and Andrews V 1975; Smith 1971). In spite of this opinion of various scholars working in the northern Mara lowlands, this view still seems to be a minority report among Maya archaeologists (Willey and Shimkin 1973:470-472). This problem of the relationship of the Puuc sites to the southern centers goes to the very heart of historical problems in the Yucatecan lowlands, as indeed it does to the later Pre-Columbian history of the entire Maya area. An architectural and chronological study of Chichén Itzá cannot, unfortunately, settle these important problems in Maya archaeology, but including Chichén Itzá in a detailed discussion of the regional archaeology brings into sharper focus and makes more explicit the factors favoring differing views. The ground becomes less firm as one moves from observation and description of architecture, to the construction of an architectural history for a site as large as Chichén Itzá, then linking this architectural sequence to absolute dates, and ultimately making historical statements from the architectural study. Most authors who have written archaeological history of Chichén Itzá and the northern Maya lowlands have relied heavily upon the available written sources to interpret the late Maya archaeology of the peninsula. Thompson cautions that the archaeologist neglects this wealth of ethnohistory at his peril (1970a:47). Whereas it is certainly desirable ultimately to link the archaeology and ethnohistory, reliance on ethnohistoric data to interpret the archaeological remains of Yucatán has led to confusing and conflicting statements about the prehistory of Yucatán and to the lack of problem orientation in archaeological investigations. This monograph does not try to reconcile the ethnohistoric information with the archaeological data, but attempts to understand the later Pre-Columbian history of the Maya area directly from hard archaeological materials. The imprecision of our archaeological and chronological knowledge makes this difficult but nonetheless important so that ethnohistoric sources can be more accurately interpreted in future.