Cross vaults are important structural elements of architectural heritage, and their seismic vulnerability has been demonstrated in past earthquakes that have resulted in significant cultural and economic losses. The complexity of their three-dimensional response, which strongly depends on  boundary conditions, structure geometry, quality of masonry as well as the properties of mortar joints, poses significant challenges  for developing representative numerical models. As part of the REVHEAL project (Structural Rehabilitation of Vaults in Heritage Asset Learning: collapse identification and design of compatible strengthening systems supported by adaptive 3D models), a full-scale clay brick masonry cross vault (plan dimensions of 3.5 x 3.5 m and height of 0.9 m) was tested under reverse cyclic loading to assess its response to in-plane shear displacements.. Dynamic identification with piezoelectric accelerometers under ambient vibrations was performed both before and after test. The data obtained allowed the identification of the natural frequencies and mode shapes of the vault in both undamaged and damaged states. These results provide a basis for future investigations to assess the sensitivity of the dynamic response to structural degradation and to explore the potential of non-invasive monitoring strategies for historic structures.