The present study focuses on the dynamical characterization of the bell tower adjacent to St. Michele Arcangelo Cathedral in Casertavecchia, Italy. The ancient tuff-masonry tower, which was built in the 13^th century, is 32 meters high and presents Gothic influences, as it is clear from the large ogival arch supporting the first level. A geometrical model of the tower was created, based on an accurate survey realized by means of 3D laser scanning technique. Also, some physical tests were performed to investigate the materials constituting the tower. Once that preliminary information was acquired, Ambient Vibration Tests (AVTs) were performed by using tri-axial and bi-axial accelerometers. The recorded data allowed for the identification of the fundamental frequencies and mode shapes of the structure under consideration. Then, a Finite Element model was built in Abaqus software and a model updating process performed to correctly reproduce the dynamical behaviour of the structure.