The emergence of first generation states is among anthropology's most enduring points of research. Such a state emerged around A.D. 500 in the southern Lake Titicaca Basin, at Tiwanaku. This state shares many characteristics with other early states, but the process of its formation was distinct. Traditional state origins models do not adequately explain the preceding centuries, when there was an unprecedented historical rupture in social organization. This dissertation follows a perspective of emergent practice, which locates the cause and production of social change in practices, traditions, and interactions, from which social groups and institutions emerge. This perspective outlines general processes of social change, while detailed genealogies of practices are necessary to document specific historical trajectories.

During the Late Formative, the southern Lake Titicaca Basin was dotted with ceremonial centers with earthen mounds, sunken temples, carved monoliths, and residences. These centers and their communities were larger and qualitatively different than anything prior, but little is known about their builders, residents, and visitors. Residents' domestic practices at Khonkho Wankane and Kk'arana, Tiwanaku provide data on the social groups that formed the communities at each site. Residents shared many cultural practices and traditions. Walled compounds were home to large, powerful social groups. There is little evidence of status differences, trade specialization, or competition. The fundamental process to increasing complexity was organizing gatherings and work-parties, which framed dense networks of interactions. Residents hosted events in walled, outdoor spaces, and served food or drink in red-rimmed Kalasasaya small jars and bowls. The populations of these ceremonial centers was relatively low, and temporary visitors were recruited, generating labor forces that built many large construction projects. Interactions at these centers generated large communities focused at ceremonial centers, and were central to the emergence of the state at Tiwanaku. Despite this radical change in social organization, many domestic practices and traditions first established during the Late Formative would be continually reproduced for hundreds of years.