Evidence from the Tuxtla Mountains in southern Veracruz suggests that Teotihuacan established a base at Matacapan, the region's top-ranking center, sometime during the Early Classic period. This development in Tuxtlas's prehistory was associated with the founding of Matacapan, a major shift in settlement pattern, and the presence of substantial amounts of Fine Buff, a lower fired variant of Fine Orange that resembles Copa ware, a common Middle Classic-period ceramic service ware at Teotihuacan. Teotihuacan's influence at Matacapan, as monitored ratios of candelero- and tripod support to rim sherds, increased markedly in the succeeding early Middle Classic period but declined in the late Middle Classic and early Late Classic periods. At the same time, Teotihuacan's influence extended well into the countryside, where it was present not only at other large sites, but also at small villages and hamlets. These developments were associated with changes in the amount and kind of obsidian traded to the Tuxtlas. The total volume of obsidian traded to the Tuxtlas in the Middle and Late Classic periods was huge: from 7.5 to 19.6 metric tons per year. Matacapan had preferred status as far as the consumption of green obsidian was concerned, and in general, pre-Hispanic settlements in the Tuxtlas consumed more of this material than neighboring areas such as La Mixtequilla and the Hueyapan region. When Teotihuacan declined in importance and its influence throughout Mesoamerica waned, a much smaller amount of obsidian—in particular, material from Pachuca—was traded to the Tuxtlas. This is precisely what we would expect if the Central Mexican city was no longer the conveyor of obsidian over long distances, and some other center—perhaps Cantona or El Tajin—replaced Teotihuacan as the primary distributor of obsidian to southern Veracruz.