1576 inner and outer basins by Giacomo Della Porta (1533/1602) for Gregory XIII Boncompagni (1572/85)
It remained undecorated for 300 years until the 1873 contest that decided the decoration
At the center "Neptune's fight with an octopus" by Antonio Della Bitta (1807/c.1879)
Around "Nereids, cherubs and sea horses" by Gregorio Zappalà (1833/1908) placed in the fountain in 1878
Zappalà had designed a black woman (a "Mora") to give a symmetrical company to the "Moro" of the fountain on the south side of the square, but the Neptune by Della Bitta was chosen instead
