Given the particular difficulty in classifying and defining the characteristics of the structural systems of historical buildings, especially when they are part of complex historical constructions, the vulnerability study efforts becomes significantly more difficult than the study of regular modern structural systems. Furthermore, old buildings may have been altered repeatedly over time, may be founded on older buildings that got buried over and could be connected one to the others. This will cause dynamic interactions with other buildings or sub-structures during an earthquake. Therefore, the particular architectural and structural history of each structure adds uncertainties in the assessment of its seismic vulnerability. In this paper the dynamic response of CEDRAV building, part of the historical centre of Cerreto di Spoleto (Italy), is analyzed, by means of the data recorded by several temporary deployments of velocimeters. The complexity in assessing seismic behavior of the historical built environments is pointed out and so the dynamic interaction with adjacent buildings.