A watching brief was undertaken during work to turn the old hospital into a public library. The site began with the construction of the church of S. Rocco following a vow made by the community during the plague of 1511; in 1797 the confraternity of S. Rocco was abolished and the building abandoned; in 1821 a hospital for the poor, designed by Bicelli, was built on the site. _Area of the presbytery and the apse_ Here stood the high altar, reached a series of steps; the apse was polygonal with vertical exterior mouldings. In place of the altar Bicelli had a well dug to provide fresh water in the summer. The excavation undertaken near the wall at the base of the main supporting arch led to the identification of the interior decoration (gold painted cornices, plaster floral decorations and fragments of wall paintings). _The sacristy_ Of this room (5,4 x 4,3 m) the perimeter of the foundation walls and part of the brick floor were revealed; on the south side were the structures in opus signinum, brick and stone slabs relating to the hospital’s bathroom and toilet facilities. _Bell tower_ An analysis of the plans from the Napoleonic land register and several observations in Bicelli’s notes place it at the corner formed by the choir/hall on the north side. _Central section (aula)_ Of notable size (23 x 11,5 m) it was divided into four bays by the large arches supporting the brick roof. All the paving and the exterior walls are conserved. The original pavement consisted of a layer of mortar covered by a thin layer of opus signinum; in some places the remains of the second brick paving survive (1600s). At the top end of the aula stood the bases of two side altars. _Atrium and portico_ The originals are still standing and were only slightly narrowed by Bicelli; the excavation revealed the original terracotta paving and the profile of the main portal. _Great staircase_ On the plan from the Napoleonic land register an elongated area can be seen up against the building’s north side, this was found during excavation and interpreted as the probable staircase leading to the upper loggia. (Paolo Chiarini)