Michelangelo moved the original to the Campidoglio in 1538 from a position near St John Lateran where it had stood since at least the eighth century. It was then believed to represent Constantine, and that misidentification probably saved the statue from papal melting pots, which consumed statues of so many non-Christian emperors and generals. In later years it was also misidentified as the Roman knight Marcus Curtius, who had saved Rome from destruction by leaping on horseback into a chasm which had opened in the center of the Forum in the time of the ancient kings. Later still, it was identified as Theodoric the Great, the Ostrogoth king. It was only in the fifteenth century that portraits on old coins pointed to the true identity of the man on horseback.
The pedestal was designed and perhaps carved by Michelangelo from one of the white marble steps of the temple of Castor and Pollux in the Forum. Michelangelo, according to legend, was so impressed with the vivacity of the statue that he commanded the horse to walk forward to its new pedestal. A more ancient legend says that there will come a morning on which the statue's gold sheathing will miraculously reappear, and on that day will be the end of the world: a voice emanating from the horse's forehead will herald the last judgement. Cola di Rienzi, undismayed by this important future mission, used the statue as a fountain at one of his overwrought banquets -- wine flowed from one of the horse's nostrils and water from the other.
Marcus Aurelius, known in his own time and until today as the philosopher emperor, was born Marcus Annius Verus in AD 121 in a house near the Lateran. He was born into a Spanish family related to the emperor Hadrian, and by the time he was eight he was already being groomed as a possible future Roman emperor. The best teachers in rhetoric, grammar, philosophy, and law educated him.
In AD 138 Hadrian adopted Antoninus Pius (of the family Aurelius) as his son, and, as part of the deal, Antoninus Pius adopted young Marcus. Marcus took Antoninus' family name, Aurelius, and after a long apprenticeship and after marrying the daughter of Antoninus (Annia Galeria Faustina), succeeded him as emperor in AD 161.
Marcus Aurelius is best known for his Meditations, which he jotted down in Greek wherever he might be during the last ten years of his life. The Stoic school of philosophy primarily influenced him and thus his Meditations are full of a preoccupation with the meaning of world-order and man's relationship to it and with the necessity for moral effort and with tolerance of one's fellow man. Disillusion and despondency in the face of the real world in which he lived also characterize them. University philosophy departments still routinely offer courses based on the Meditations.
Marcus Aurelius was a fairly good emperor in the mold of his predecessor, Antoninus, but he spent most of his reign on foreign battlefields, trying to defend the frontiers of the Empire. He eventually died while on campaign across the Danube in AD 180 in the town that became Vienna. Commodus, who rivaled Nero in his perversity and madness, succeeded Marcus Aurelius. Some historians, not wanting to believe that Marcus could beget such a creep, surmise that Commodus was really the son of one of Annia Galeria Faustina's several gladiator companions. Commodus erected the Column commemorating the victories of Marcus Aurelius that now stands in the Piazza Colonna.
The Equestrian Statue (image):
The Column in Piazza Colonna:
http://members.aol.com/Heraklit1/marcus.htm#marcus (includes a bio note on Commodus)
Full text of the Meditations:
Epictetus, the source of Marcus
Aurelius's Stoic philosophy: