It was rebuilt in 1831 after French troops set it on fire during the Napoleonic Wars.[4] Of the ancient structure only the crypt remains, which includes a primitive pagan altar. Town hall, designed by Antonio da Sangallo the Younger in the 15th century, was finally completed in the 18th. The base was of stone, embellished by a porch, and the upper part had windows and a balcony with a bell-tower.