The allegorical figure may represent the Tiber or possibly Neptune and takes its name from the forum of Mars, the name sometimes given to the Forum of Augustus because of the temple of Mars Ultor that was located there.

In the sixteenth century, the Marforio was considered to be the partner of another famous statue, named "Pasquino" after a schoolmaster said to have lived opposite the spot where it was placed in 1501 (later tradition has him to be a caustic tailor). Both were one of several "talking statues" in Rome to which placards were affixed, the one providing an ironic reply to questions posed by the other about political or social issues. These anonymous satires or lampoons, publicly ridiculing their subject (who often was the pope), were known as pasquinades, one of the most famous of which was directed at Pope Urban VIII (1623-1644) of the Barberini family: Quod non fecerunt barbari, fecerunt Barberini, "What the barbarians did not do, the Barberini did."

It refers to his removing the gilt bronze ceiling trusses from the portico of the Pantheon, which had survived from the time of Hadrian, and melting them down to make eighty cannon for the Castel Sant' Angelo, arguing that the metal would be better used to protect the church from its enemies than the rain. The bronze also is said to have been cast for Bernini's magnificent baldacchino (1624-1633) over the altar of St. Peter's basilica.

A much worn statue, thought to be Menelaus holding the body of Patroclus, the Pasquino still is to be seen in the Piazza di Pasquino, a small square off the Piazza Navona (the stadium of Domitian).