The dating of the Prima Porta piece is widely contested. It is thought to be a copy of a bronze original. The sculptor may have been Greek. This original, along with other high honors, was vowed to Augustus by the Senate in 20 BC and set up in a public place. The marble statue, however, was found in his wife's (Livia) villa.
It is also contested that this particular sculpture is a reworking of a bronze original, possibly a gift from Tiberius Caesar to his mother Livia (since it was found in her villa Ad Gallinas Albas in the vicinity of the ninth mile-marker of the via Flaminia, and close to a late Imperial gate called Prima Porta) after Augustus' death and in honor of the woman who had campaigned so long for him to become the next Caesar. This would explain the divine references to Augustus in the piece, notably his being barefoot, the standard representation of gods or heroes in classical iconography. Also, the reliefs in the heroic cuirass depict the retrieval of Crassus' standards captured by the Parthians, an event in which the young Tiberius himself took a part, serving as an intermediary with the Parthian king, in the act that is shown in the central scene of the armor, possibly his grandest service to his adoptive father Augustus. With the introduction of Tiberius as the figure responsible for the retrieval of the standards, he associates himself with Augustus, the emperor and the new god, as Augustus himself had done previously with Julius Caesar. Under this hypothesis, the dating of the statue can be placed during the first years of Tiberius' reign as emperor (AD 14 — AD 37).
Augustus is shown in this role of "Imperator", the commander of the army, as thoracatus —or commander-in-chief of the Roman army (literally, thorax-wearer)—meaning the statue should form part of a commemorative monument to his latest victories; he is in military clothing, carrying a consular baton and raising his right hand in a rhetorical adlocutio pose, addressing the troops. The bas-reliefs on his armored cuirass have a complex allegorical and political agenda, alluding to diverse Roman deities, including Mars, god of war, as well as the personifications of the latest territories he conquered: Hispania, Gaul, Germania, Parthia (that had humiliated Crassus, and here appears in the act of returning the standards captured from his legions); at the top, the chariot of the Sun illuminates Augustus's deeds.
The statue is an idealized image of Augustus based on the 5th-century BC statue of the Spear Bearer or Doryphoros by the sculptor Polykleitos. Compare the Orator in the Museo Archeologico in Florence. The Doryphoros's contrapposto stance, creating diagonals between tense and relaxed limbs, a feature typical of classical sculpture, is adapted here. The misidentification of the Doryphoros in the Roman period as representing the warrior Achilles made the model all the more appropriate for this image. Despite the Republican influence in the portrait head, the overall style is closer to Hellenistic idealisation than to the realism of Roman portraiture.
Despite the accuracy with which Augustus' features are depicted (with his somber look and characteristic fringe), the distant and tranquil expression of his face has been idealized, as have the conventional contrapposto, the anatomical proportions and the deeply draped paludamentum or "cloth of the commander". On the other hand, Augustus's barefootedness and the inclusion of Cupid riding a dolphin as structural support for the statue reveals his mythical connection to the goddess Venus (Cupid's mother) by way of his adopted father Julius Caesar. The clear Greek inspiration in style and symbol for official sculptural portraits, which under the Roman emperors became instruments of governmental propaganda, is a central part of the Augustan ideological campaign, a shift from the Roman Republican era iconography where old and wise features were seen as symbols of solemn character. Therefore, the Prima Porta statue marks a conscious reversal of iconography to the Greek classical and Hellenistic period, in which youth and strength were valued as signs of leadership, emulating heroes and culminating in Alexander the Great himself. Such a statue's political function was very obvious—to show Rome that the emperor Augustus was an exceptional figure, comparable to the heroes worthy of being raised to divine status on Olympus, and the best man to govern Rome.
It is almost certain that the Augustus was originally painted, but so few traces remain today (having been lost in the ground and having faded since discovery) that historians have had to fall back on old watercolors and new scientific investigations for evidence. Vincenz Brinkmann of Munich researched the use of color on ancient sculpture in the 1980s using ultraviolet rays to find traces of color.
Today, the Vatican Museums have produced a copy of the statue so as to paint it in the theorized original colours, as confirmed when the statue was cleaned in 1999. However, an art historian of the University of St Andrews in Scotland, Fabio Barry, has criticized this reconstitution as unsubtle and exaggerated.
Since at least the 18th century, the familiar sight of Roman sculptures that lack their original paint has encouraged the idea that monochromy is the natural condition for classical sculpture; but surface treatment is now recognized as an integral to the overall effect of the sculpture. There are many notable differences between the original Prima Porta of Augustus and the painted recreation (see recreation to the right). However, due to the ongoing disagreement on the statues pigmentation there is little information or exploration on the usage of these colors.
The writings of second-century polymath, Lucian, provide a good example of how color functioned for a work of that time, "I Fear I stand in the way of her most important feature!... the rest of the body let Apelles represent.. not too white but diffused with blood." The quote continues to state that a statue of the time is unfinished without its "chora"—skin—or layer, applied to the statue to render it complete. The specific implications of each color chosen for the Prima Porta is unknown; assumedly red for royalty.
The haircut is made up of divided, thick strands of hair, with a strand directly over the middle of Augustus's forehead framed by other strands over it. From the left two strands stray onto the forehead, and from the right three strands, a hairstyle first found on this statue. This hairstyle also marks this statue out as Augustus from comparison with his portrait on his coinage, which can also give a date to it. This particular hairstyle is used as the first sign identifying this portrait type of Augustus as the Prima Porta type, the second and most popular of three official portrait types: other hairstyles of Augustus may be seen on the Ara Pacis, for example. Another full-size statue of Augustus with these "Primaporta type" features is the Augustus of Via Labicana, portraying Augustus in the role of Pontifex Maximus, now in the Museo Nazionale Romano.
The face is idealized, as with those of Polykleitos' statues. Art underwent important changes during Augustus's reign, with the extreme realism that dominated the republican era giving way to Greek influence, as seen in the portraits of the emperors - idealizations summarizing all the virtues that should be possessed by the exceptional man worthy of governing the Empire. In earlier portraits, Augustus allowed himself to be portrayed in monarchical fashion, but amended these with later more diplomatic images that represented him as "primus inter pares". The head and neck were produced separately in Parian marble and inserted to the torso.
The statue's iconography is frequently compared to that of the carmen saeculare by Horace, and commemorates Augustus's establishment of the Pax Romana. The breastplate is carved in relief with numerous small figures depicting the return, thanks to the diplomacy of Augustus, of the Roman legionary eagles or aquilae lost to Parthia by Mark Antony in the 40s BC and by Crassus in 53 BC.
The figure in the centre, according to the most common interpretation, is the subjected Parthian king returning Crassus's standard to an armored Roman (possibly Tiberius, or symbolically Mars Ultor). This was a very popular subject in Augustan propaganda, as one of his greatest international successes, and had to be especially strongly emphasized, since Augustus had been deterred by Parthian military strength from the war which the Roman people had expected and had instead opted for diplomacy. To the left and right sit mourning female figures. A figure to one side with a sheathed sword personifies the peoples in the East (and the Teutons?) forced to pay tribute to Rome, and one on the other side with an unsheathed sword obviously personifies the subjected peoples (the Celts). From the top, clockwise, we see:Caelus, the sky god, spreading the tent of the sky
Aurora and Luna
the personification of the subjected peoples
the goddess Diana
the earth goddess Ceres/Tellus - similarly represented on the Ara Pacis
Apollo, Augustus's patron
the personification of the tributary peoples
the sun god Sol
a Sphinx on each shoulder, representing the defeat of Cleopatra by Augustus
None of these interpretations are undisputed. The gods, however, probably all symbolize the continuity and logical consistency of the events - just as the sun and moon forever rise, so Roman successes are certain and divinely sanctioned. Furthermore, these successes are connected with the wearer of this breastplate, Augustus. The only active person is the Parthian king, implying that everything else is divinely desired and ordained.
During his lifetime, Augustus did not wish to be depicted as a god (unlike the later emperors who embraced divinity), but this statue has many thinly-veiled references to the emperor's "divine nature", his genius. Augustus is shown barefoot, which indicates that he is a hero and perhaps even a god, and also adds a civilian aspect to an otherwise military portrait. Being barefoot was only previously allowed on images of the gods, but it may also imply that the statue is a posthumous copy set up by Livia of a statue from the city of Rome in which Augustus was not barefoot.
The small Cupid (son of Venus) at his feet (riding on a dolphin, Venus's patron animal) is a reference to the claim that the Julian family were descended from the goddess Venus, made by both Augustus and by his great uncle Julius Caesar - a way of claiming divine lineage without claiming the full divine status.
The Prima Porta-type of statues of Augustus became the prevailing representational style for him, copied full-length and in busts in various versions found throughout the empire up until his death in 14. The copies never showed Augustus looking older, however, but represented him as forever young, in line with his propaganda goals.