Historical Seismology is a largely multidisciplinary scientific field devoted to investigating earthquakes of the past and to interpreting their effects against the backdrop of their sociocultural and economic context (Guidoboni and Ebel, 2009).

Studying historical seismicity requires an exhaustive search of all historical records. Furthermore, the nature of the documents (primary or secondary source) plays an important role in interpreting the impact of the earthquake and the resulting uncertainty.

Hereinafter, it will be stated whether the used document is a primary or a secondary source. The used written records are of various types : parochial register, anonymous testimony, log book or journal paper.

The project collect both historical information describing the impact of past earthquakes on the city of Siena and that describing routine maintenance works that changed the buildings geometry and the use of new materials over time.

An in-depth study of historical records can deliver information on the occurrence of these circumstances, their impact on the buildings and on the associated restorations, providing exact chronological markers.