The east side of the square is dominated by a monumental fountain surrounded by balustrades. The lower basin is divided into nine sides and is adorned by three lions of the city. A central balustrade holds up a second round basin, which supports another balustrade with a cone. We also have knowledge of a larger fountain of the Comune from 1303. In 1467, it was rebuilt by Polimante di maestro Gentile, with stone tables and little columns and the coats of arms of Paolo II Barbo and the Papal Treasurer. The fountain, as it is today, was rebuilt in 1772 by Giuseppe Martinucci, mason of Assisi, from a drawing by Architect Valeri.