Palace of Reverenda Camera Apostolica, was built around 1580 by Pope Gregory XIII and housed the administration offices of the alum mines. The ‘Reverend Apostolic Chamber’ was the papal administration financial organ and also ruled justice. The building housed the papal court during visits to the mines and for this initially it was called 'Government House'. The symbol of the Reverend Apostolic Camera (the two papal keys over an open umbrella) is still visible on the clock tower on the facade. The Palace was purchased by the Town Council in 1950 and houses the museum and the library.