Some historians assert that a conquered enemy was originally part of the sculpture (based on medieval accounts, including in the Mirabilia Urbis Romae, which suggest that a small figure of a bound barbarian chieftain once cowered underneath the horse's front right leg).

While the horse has been meticulously studied in order to be recreated for other artists' works, the saddle cloth was copied with the thought that it was part of the standard Roman uniform.

Its original location is debated: the Roman Forum and Piazza Colonna (where the Column of Marcus Aurelius stands) have been proposed.

Indeed, that of Marcus Aurelius is one of only two surviving bronze statues of a pre-Christian Roman emperor; the Regisole, destroyed after the French Revolution, may have been another.

The equestrian statue of Marcus Aurelius in Rome owes its preservation on the Campidoglio to a common misidentification of Marcus Aurelius, the philosopher-emperor, with Constantine the Great, the Christian emperor; indeed, more than 20 other bronze equestrian statues of various emperors and generals had been melted down since the end of the Imperial Roman era.

[4][5] It has been speculated that its misidentification stems from the prior existence of an equestrian statue of Constantine which had stood beside the Arch of Septimius Severus, and which had been most likely taken on the orders of the emperor Constans II during his visit to Rome in 663.

[6] In the Middle Ages this was one of the few Roman statues to remain on public view, in the Campus Lateranensis, to the east of the Lateran Palace in Rome, from 1474 on a pedestal provided by Pope Sixtus IV.