The quantification of historical earthquakes is a key element in seismic hazard assessment. Historical buildings recorded in their walls disorders induced by ancient earthquakes as "stone seismometers". We developped an innovative methodology to infer key ground motion characteristics of historical earthquakes by connecting building archaeology, seismology and earthquake engineering through the case study of the medieval church of Sant'Agata del Mugello (Central Apennines, Italy) for which many historical sources described the damage induced by past earthquakes, and their post seismic repair. The largest known events occurred in 1542 (Mw 6) and 1919 (Mw 6.3). The church's history is described by combining stratigraphic analysis of walls with an in-depth study of archives. Ambient vibration measurements provide a structural identification of the church in its present state. A preliminary model of the church is updated through a Vibration-Based model updating process. Strategies to compute the seismic response of the church are discussed. Preliminary results using a continuum damage model to identify the limit of the updated model is discussed.