[Paper Review] Todos estos edificios se hacen de diverso modo que en Europa: Estudio arqueoastronómico de las iglesias jesuíticas de Chiquitos

Alejandro Gangui|arXiv (Cornell University)|Feb 1, 2026

Historical and Architectural Studies0 citations

TL;DR

The paper analyzes the spatial orientation of eight standing Jesuit churches in Chiquitos (Bolivia) plus a ninth ruin and a tenth from plans/maps to explore architectural alignment patterns and possible astronomical influences.

ABSTRACT

The study of the spatial layout of Christian churches has been of great interest since late Antiquity and the beginning of the Early Middle Ages, and has received a new impetus in recent literature when it was recognized that the orientation of their main axes represents a key feature of their architecture. From the earliest Christian communities, the orientation of the church allowed the faithful to pray facing the east, towards the rising Sun. Several authors were careful to point this out in their writings; in particular, prior to the Council of Nicaea (325 AD), the Apostolic Constitutions indicated: "And let it be, first, the elongated building, with its head facing east". We present a detailed analysis of the spatial orientation of the historic churches located in the Jesuit towns of Chiquitania (Bolivia). We have measured in situ the main characteristics of eight churches currently standing and the ruins of a ninth construction. In all cases, we carry out a thorough survey of the landscape surrounding each church, trying to find some common pattern, possibly astronomical, that explains its orientations. To our list we also add the orientation measures of a tenth church based on work with plans and satellite maps. We complement our data with a detailed cultural and historical study of the characteristics of missionary towns. Unlike the churches of the Guarani towns of the historic province of Paraquaria where the meridian orientations stand out, in the case of the Jesuit churches of Chiquitos, half of the measured constructions show orientations that fall within the solar range, with three churches oriented equinoctially with high precision. We analyze the reasons for these orientations and delve further on the possible relevance that lighting effects could have had for the architects of these churches, which represent true hidden cathedrals in the virgin tropical forest.

Motivation & Objective

• Investigate whether the church orientations in Jesuit towns of Chiquitania align with astronomical patterns.
• Assess how the Chiquitos churches differ from European orientational norms.
• Provide a cultural-historical context for the architectural choices in missionary towns.

Proposed method

• Conduct in-situ measurements of the main characteristics of eight standing churches and the ruins of a ninth construction.
• Supplement field data with orientation measures of a tenth church based on plans and satellite maps.
• Perform a thorough landscape survey around each church to identify potential patterns or astronomical explanations.
• Include a detailed cultural and historical study of the characteristics of the missionary towns.

Experimental results

Research questions

• RQ1 Do the orientations of the Chiquitos Jesuit churches show a preference for solar-range, meridian, or equinoctial alignments?
• RQ2 What historical, lighting, or landscape factors might explain the observed orientations?
• RQ3 How do the Chiquitos churches compare to the Guarani churches in Paraquaria regarding orientation patterns?
• RQ4 What is the role of lighting effects in shaping architectural choices for these churches?

Key findings

• Half of the measured constructions fall within the solar range.
• Three churches are oriented equinoctially with high precision.
• A tenth church orientation was assessed using plans and satellite maps to complement in-situ data.
• The study provides a cultural-historical context of missionary towns to interpret the spatial orientations.