Inca human sacrifice and sacred pilgrimages: spatial analysis of sites on the Chachani and Pichu Pichu volcanoes

Abstract

The capacocha was one of the most important types of Inca sacrifices. Road stations (tambos) were built for the pilgrims who travelled to mountain peaks with the sacrifices. Spatial analysis of two tambos on the slopes of the Pichu Pichu and Chachani volcanoes in Peru reveals segregation in the sacred landscape.

Introduction

Religiosity in the Inca Empire (c. AD 1400–1572) was strongly related to the landscape, ethnicity and common ancestor cults (Szemiński & Ziółkowski 2021). One of the most important sacrifices performed by the Incas was the capacocha—the sacrifice of children, chosen from elite provincial families, and acllas (virginal young women dedicated to the Sun deity; Cobo 1893; Hernández Príncipe 1923). In the provinces, the capacocha was made for the huacas (deities, sacred places) and was often associated with mountain peaks. The procession of the victims, accompanied by feasts, primarily started in Cusco and could take many months to reach provincial shrines (Reinhard & Ceruti 2010). Only a few capacocha offerings have been discovered, mostly on the mountain peaks of northern Chile, southern Peru and north-western Argentina (Reinhard & Ceruti 2010).

Tambos were waystations along the Inca royal roads, for administrative and military purposes. Many Inca roads led directly to mountain summits and the remains of tambos on the slopes of some volcanoes suggest that they were also created for religious activities. High-mountain tambos were the last stops for the capacocha pilgrimage before climbing to the summit, and some are located in the cordillera ecozone above 4800m above sea level (Linares Málaga 1966; Reinhard & Ceruti, 2010). The use of such stops by the pilgrims was dictated by the distance to the main administrative centre and access to water, which in turn determined the number of pilgrims. Licancabur tambo (on the Chilean side of the volcano) had over 150 structures and could host several hundred people (Reinhard et al. 1980). At the tambo located on the slope of Llullaillaco (Argentina), the remains of everyday activities suggest that this place was temporarily occupied (Ceruti 2003; Bray et al. 2005).

In 2022, a project to study the sites associated with the last stage of the capacocha pilgrimage was launched. The project aims to analyse the spatial architecture management of two tambos on the Chachani and Pichu Pichu volcanoes (Peru) (Figure 1). The preliminary analysis based on the 3D models of the visible structures indicates the segregation of the buildings according to their function and their relationship to the sacred landscape.

Figure 1. Map of the region showing the locations of the volcanoes discussed (figure by authors, base map from Google Earth).

Spatial analysis of Chachani and Pichu Pichu tambos

The tambos of Chachani and Pichu Pichu were selected due to the confirmed location of the capacocha burials at both summits (Beorchia 1985; Linares Málaga 1966; Reinhard & Ceruti 2010; Socha et al. 2021). The tambos were discovered during expeditions to the summits in 1965 and 2012.

During the survey in 2022, photogrammetry was performed to obtain 3D models of the most important structures concerning the sacred landscape. Photogrammetric imagery and satellite mapping were used for precise documentation, which allowed the collection of accurate measurements and calculation of site capacity estimates. At both Chachani and Pichu Pichu, the tambos are divided into two sections: a larger, lower elevation area and a higher elevation area characterised by smaller buildings.

Lower tambo of Chachani

The lower part of the Chachani tambo covers a total area of around 0.1ha. It consisted of 14 buildings organised in two kanchas (house grouping around a courtyard) (Figure 2). Two oval-shaped structures resemble Inca granaries. Outside of the kanchas, there is a ceremonial plaza of 250m². The location was probably chosen owing to the size of the natural plateau.

Figure 2. Plan and 3D model (red square) of the lower Chachani tambo (figure by authors).

Upper tambo of Chachani

The upper part of the tambo is located 250m south-east of the lower one. It consisted of one structure built against a large rock. A natural flattened area slopes gently down from the top of the boulder to the entrance wall of the building. On the side of the boulder that borders the building, a partially carved area may have given direction to the flow of liquids (Figure 3). The distance from the upper tambo to the summit is estimated to be around six hours of climbing. Along the path to the summit, the Incas made small shelters where the pilgrims could rest, the walls of which are still standing.

Figure 3. Plan and 3D models of building at the upper part of Chachani tambo (figure by authors).

Lower tambo on Pichu Pichu

The lower part of Pichu Pichu tambo was organised like the Chachani one. It covered about 0.15ha of a large, flat area. The concentration of petroglyphs was recorded during a survey in 1966 (Linares 1966). The 750m² main plaza is oriented toward the valley with a view of nearby summits (Ubinas and Pacoorcco) (Figure 4). Due to vegetation cover and a thick layer of volcanic ash, not all buildings are visible, but it was possible to identify eight structures.

Figure 4. Plan and 3D models of building at the lower part of the Pichu Pichu tambo (figure by authors).

Upper tambo on Pichu Pichu

The upper part of the Pichu Pichu tambo is 140m to the south-east of the lower one. It consisted of one building with three separate rooms (Figure 5). In front of the tambo there is a rock resembling the shape of Pichu Pichu. It is possible that the rock was carved to represent the summit (Figure 6).

Figure 5. Plan and 3D model of building at the upper part of Pichu Pichu tambo (figure by authors).

Figure 6. Rock carving with outline comparable to the profile of the Pichu Pichu summit (figure by authors).

Discussion and conclusion

The spatial structures of the tambos, according to the new data and previous research, relate to the sacred landscape and the division of pilgrims by social rank. The pilgrimage was attended by people of different social status, Incas, priests, victims and their families and ordinary pilgrims associated with the local huaca cult. The size of the main plazas in the lower parts of the tambos suggests they were built to host many pilgrimages, being the last area with easy access before the summit. Plazas could accommodate hundreds of pilgrims (assuming about 1m² per person), although it seems unlikely that so many people could be there at the same time. Plazas may also have been designed as places for rituals that pilgrims could observe from outside the designated space.

The upper parts of the tambos were probably used for rituals attended by fewer people. The veneration of capacocha victims included divination, which was performed in secluded places. These oracles performed an important role in the Inca State as all important religious, political, military and economic matters required consultation with deities. Hernández Príncipe (1923) records that the oracle of the capacocha mummy of Tanta Carhua was located below the hill on which the mummy was buried. It is possible that the upper tambos had a similar function. The boulder at Chachani shows signs of water flow and it is possible that the rock was the place of a ritual liquid flow used in divination to invoking water from a volcano. The capacocha was strongly associated with the cult of water and fertility and was often celebrated to prevent drought (Cobo 1893).

Ongoing research will focus on biochemical analysis of artefacts from the tambos to determine the possible origins of the pilgrims and establish a local chronology. Another aim of the project is to document other sites related to the capacocha to establish architectural patterns, Inca management of the ritual and its role in the exercise of power by the state.