The fountain in Piazza Colonna was designed by Giacomo della Porta (1532-1602), and carved by Rocco Rossi between 1575 and 1577. The marble basin is decorated with the heads of sixteen lions. A circular stone vasque once stood on a pedestal in the centre of the fountain and water poured from it into the basin.
In 1830, the architect Alessandro Stocchi replaced the original vasque with the one we see today and added the two pairs of entwined dolphins.