The “Arco di Portogallo” or “Arch of Portugal”, so called because it was located in the Corso in Rome near the residence of the Portugese ambassador, was demolished in 1662. I had never heard of it, I confess, until Anna Blennow tweeted an engraving by Piranesi. It stood near the Palazzo Fiano. It seems to have been a late edifice, perhaps of the time of Marcus Aurelius, perhaps later.
Let’s enjoy this image of another bit of vanished Rome.