For existing structures, the development of seismic vulnerability studies requires the availability of information related to geometry, boundary conditions, material properties, and accumulated damage. In the case of historical constructions, modern conservation criteria recommend carrying out a comprehensive structural assessment that involves the use of concurrent experimental diagnosis complemented with numerical and analytical approaches for structural analysis. This paper presents a proposal for a comprehensive integration of these perspectives by the application of several tools for the seismic performance analysis of an iconic Andean historical adobe building: the 'San Pedro Apostol Church' located in Andahuaylillas, Southern Peru. In this church, several non-destructive techniques for geometrical and damage assessment were combined with structural exploration tools, nonlinear numerical modeling, and simplified analytical tools for performing predictive seismic analysis. The results indicate the feasibility of the integration of these techniques for studying existing earthen buildings and their capacity to properly predict observed damage in past earthquakes (i.e. failures of bell towers, façade walls, tympani, and triumphal arches). In particular, the analyses allowed the identification of high seismic vulnerability of the studied church in occasional earthquakes (earthquakes with a return period of 72 years) due to the activation of collapse mechanisms consisting of rocking of the façade walls and out-of-plane overturning of the lateral walls.