Between about 250 and 550 CE, an interval spanning several ceramic phases, Teotihuacan was at its height. Changes in spatial patterns of occupation within the city were not dramatic. Sherd densities tend to increase in areas somewhat removed from the Avenue of the Dead, especially in a broad eastern and southern region and in the far northwest (the northwesternmost part of the large Oztoyahualco district). Most notable was further increase in the far northwest, increase in the Tlajinga district in the south (where by now there were some workshops of specialized potters), and decline along most of the Avenue of the Dead. Figure 7.1 shows the spatial distribution for the Xolalpan phase, the latter part of this period.

Population and Housing

Before dealing with other aspects of Teotihuacan during this interval, it is necessary to come to grips with the task of estimating population. This is the first period for which there is enough evidence about residential architecture to make the attempt feasible. My estimates for earlier periods are based on TMP sherd counts, the assumption that sherds produced per person per year did not vary much over time, and assumptions about the durations of ceramic phases. They are all very rough estimates. It is natural to suppose that ceramics of early periods would be underrepresented in surface collections. But if that was the case at Teotihuacan, populations of earlier periods must have been far larger than those later than 250 CE, which is highly improbable. Excavations in tracts that had large enough surface collections to make sampling vagaries small have not found abundant sherds of earlier phases that were not well represented in the surface collections. Probably this is because deposits are usually not deep and because earlier material was often recycled for use in the fill of later structures.

It has been hard to dispel the belief that the population of the city continued to grow and reached a peak sometime in the 400s or 500s.