The doorway opens beneath a 14th-century carved group: the Madonna and Child between the patron saints, and St Peter receiving the keys while holding a scroll — «Tu es Petrus, et super hanc petram aedificabo ecclesiam meam». Behind that door there is no museum: there is the home of the Società di Mutuo Soccorso fra Carpentieri e Calafati — the Mutual Aid Society of Carpenters and Caulkers — the oldest association still alive in Venice.