This study investigates worldview and ideology during the late Terminal Formative period (A.D. 100 – 250) in the lower Río Verde Valley of Oaxaca, Mexico, through an analysis of iconography found on grayware ceramic serving vessels. The sample includes 457 vessels and sherds from 17 lower Verde sites obtained through excavations and surface collections between 1988 and 2009. Drawing upon theories of semiotics and style, this thesis identifies a suite of icons suggesting that ceramics were a medium for expressing regionally shared beliefs. Chatino potters carved common Formative period Mesoamerican themes into the walls of graywares, such as depictions of maize and climatic phenomena, which may have been part of a religious worldview rooted in the belief that humans and non-human deities shared a reciprocal relationship. People at Río Viejo, including elites, may have attempted to exploit this relationship, thought of as a ―sacred covenant‖ or agreement between humans and deities, to create a more centralized political entity during the late Terminal Formative Chacahua phase. By using iconographic graywares in socially and politically significant ritual activities such as feasting and caching events, elites imbued graywares with a powerful essence that would have facilitated the spread of the coded messages they carried. Based on statistical analyses of the diversity of iconographic assemblages from various sites, I argue that the assemblage of icons at Río Viejo, a late Terminal Formative political center in the lower Verde, indicates ideas likely originated at or flowed through this site.