The investigation of the earthquakes of the past is a well established topic in the field of seismology. Its peculiar characteristics reside in using historical documentation and early instrumental recordings to describe effects and assess the size and the source parameters of the earthquakes occurred in the past centuries. Each of these two approaches has its own methodology and interpretative processing of the data, both with the aim of providing seismological data comparable and compatible with the modern, instrumentally recorded ones. A reliable evaluation of seismic hazard depends upon the availability of high-quality seismological data to be squeezed into the parametric records of today seismic catalogues, which have to extend as much as possible back in time.
The interest of an international debate on methods and results in this field lies in the need to learn as much as possible about, in the different European countries but worldwide also, how the historical documents and the recordings were produced, how they were retrieved and stored by the seismological institutions, and finally if and how their most recent interpretation has been reported and made available to the scientific community.
Contributions describing the practice in the investigation as well as the adopted archiving solutions are welcome, together with the illustration of case histories of large earthquakes, the understanding of which benefited from both the historical documents and the early instrumental recordings.