The coat of arms of the rione depicts a rampant griffon, a Greek mythological creature with the head of an eagle and the body of a lion.

In this area Domitianus built his stadium and an Odeon (Odeum in Latin), for musical and poetic competitions.

In 1500 most of the commercial activity slowly moved from Campo de' Fiori to Piazza Navona, that was the favorite place since it was wider.

From this period until Rome became capital of unified Italy in 1870 there were no major changes but the opening of Corso Vittorio Emanuele II, a great street having a flexuous track in order to avoid the already existing palaces.

Northward, the rione borders with Ponte (R. V), whose boundary is defined by Piazza delle Cinque Lune, Piazza di Tor Sanguigna, Largo Febo, Via di Santa Maria dell'Anima, Via di Tor Millina, Via della Pace, Piazza del Fico, Via del Corallo, Via del Governo Vecchio, Via dei Filippini and Vicolo Cellini.