Archaeological cultures present allegories of ethnic identities across the centuries or millennia but such conceptualisations are necessarily incomplete and lack the resolution to explore transitions between cultures. Here, exploration of the archaeological contexts, production methods, stylistic variation and radiocarbon dating of 20 preserved textile fragments facilitates an examination of cultural change at Huaca del Sol (Huacas de Moche, northern Peru). While occupants of the site experienced many outside cultural influences, including those from the highland Wari Empire, continuity in textile traditions suggests that some sense of Moche identity was maintained through the tenth century and after the perceived end of the Moche culture.

During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and distances than ever before identified in the Andes, in part by the expansionary Wari state. Two of the three major obsidian sources used in the south-central Andes are located in the modern department of Arequipa, Peru. Arequipa was a region of intense Wari influence and intrusive presence; however, little is known about regional obsidian use. Portable X-ray fluorescence (pXRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used to analyze 383 obsidian artifacts recovered from 10 archaeological sites in Arequipa. Results highlight diachronic and spatial patterning related to obsidian procurement strategies, state versus bottom-up exchange networks, and local participation within the Wari realm. A wide variety of geological obsidian sources, including nonlocal obsidians originating from Wari's Ayacucho heartland, were used. By the late Middle Horizon, the Wari had consolidated regional resources with the sole use of Alca-1 and Alca-4 bedrock obsidians, the largest-sized and highest-quality sources in the area. We assess related models of obsidian procurement and exchange related to state political economy, long-distance caravan activity, and the role of local ceremonial/waystation centers that facilitated the flow of ideas, goods, and people across Arequipa.

Processual models of the early state envisioned hierarchical societies with stable social and political structures. More recent research, however, has questioned this vision. Here, the authors explore Middle Horizon (AD 700–1000) Wari state iconography to provide an example of early state social and political organisation from the Central Andes. Social network analysis (SNA) of human figures (‘agents’) depicted in Wari art identifies links between individual agents, as visualised on objects and between the objects’ findspots. The results suggest that the Wari state was more heterarchical than previously imagined. Similar applications of SNA could be used to explore the iconographic evidence of other early, pre-literate states around the world.

In the pre-Columbian Andes, the use of hallucinogens during the Formative period (900–300 BC) often supported exclusionary political strategies, whereas, during the Late Horizon (AD 1450–1532), Inca leaders emphasised corporate strategies via the mass consumption of alcohol. Using data from Quilcapampa, the authors argue that a shift occurred during the Middle Horizon (AD 600–1000), when beer made from Schinus molle was combined with the hallucinogen Anadenanthera colubrina. The resulting psychotropic experience reinforced the power of the Wari state, and represents an intermediate step between exclusionary and corporate political strategies. This Andean example adds to the global catalogue documenting the close relationship between hallucinogens and social power.

A recent survey in the Ingenio Valley provides new insight into the nature of the Middle Horizon on the south coast of Peru. A reconsideration of the Tres Palos I and II sites could provide a new perspective on Wari expansion into the region.

The highland Wari (AD 600–1000) were an influential and expansive Andean civilisation, yet the nature and organisation of Wari power is debated. For example, it is suggested that coastal Nasca was governed by Wari, but doubts remain about its role in the region. Recent excavations at Huaca del Loro in Nasca have uncovered rectilinear compounds, a D-shaped temple, a large cemetery and a domestic area. The authors suggest that this evidence reflects Wari colonisation, undertaken during a period of primary expansion, on a site with long-established ties between Wari and Nasca. The use of multiple colonising strategies and local responses may reflect imperial situations in other world civilisations.

A common feature of successful ancient states was the role of elites in maintaining and regulating socioeconomic structures and, in particular, emphasising their own social difference. The Wari (AD 600–1000) are considered the earliest expansive state in South America, and excavations have demonstrated the rich variety of exotic goods imported from across the region into the polity's heartland. Here, the authors argue that the importation of raw materials, plants, animals and people from distant regions was crucial for defining and sustaining Wari social differentiation and ideology. They emphasise the importance of studying material provenance and their archaeological contexts in order to understand the role of exotic goods in legitimising ruling groups in ancient states.

In this article, I investigate the Northern and Southern Moche archaeological cultures by evaluating the data gathered and theories developed since their first identification 25 years ago. I suggest that what was previously considered the Southern Moche tradition was the dominant one throughout most of the North Coast, with regional variations, prior to about AD 650. After that date, the “Classic Moche” tradition ended in both regions and was succeeded by distinct Northern and Southern ceramic and mortuary traditions and, inferentially, reorganized social, political, and religious systems as well. The relations between regional mortuary and other traditions and fineware styles are considered in light of pan-regional dynamics including the ascendancy of the Wari Empire.

The impact of Amazonia on the history and development of late prehistoric (c. AD 500–1500) Andean highland polities has been largely ignored. This article considers how shifting exchange relations between Amazonia and the Andes may have greatly influenced state-formation processes. It is argued that Arawak expansion in the Amazonian lowlands, completed by c. AD 500, was a prerequisite development for stimulating the rise of Andean highland empires, which were heavily dependent upon imported prestige Amazonian feathers. Future research directions are suggested in order to enhance our understanding of late prehistoric state formation in the Americas.

Recording devices formed of knotted cords, known as khipus, are a well-known feature of imperial administration among the Inka of Andean South America. The origins and antecedents of this recording system are, however, much less clearly documented. Important insights into that ancestry are offered by a group of eight khipus dating from the later part of the Middle Horizon period (AD 600–1000), probably used by the pre-Inka Wari culture of the central Andes. This article reports the AMS dating of four of these early khipus. A feature of the Middle Horizon khipus is the clustering of knots in groups of five, suggesting that they were produced by a people with a base five number system. Later, Inka khipus were organised instead around a decimal place-value system. Hence the Inka appear to have encountered the base five khipus among Wari descendant communities late in the Middle Horizon or early in the Late Intermediate period (AD 1000–1450), subsequently adapting them to a decimal system.

Eating shellfish in the wrong season makes you ill. But early people of the Andes seem to have courted these effects to gain out-of-body experiences. It may have been these effects, as well as its distinctive colouring and appearance, that made Spondylus such a very special commodity.