The complex of the Ara Pacis Augustae, an altar dedicated in 9 BCE, stood in the Campus Martius. The building was erected by the Senate to celebrate Augustus’s return from Spain and Gaul in 13 BCE. The platform of the altar was surrounded by a high screen wall, embellished with sculptures inside and outside. Within the enclosing precinct walls, the altar itself was carved with images illustrating the lex aria, the law governing the ritual performed at the altar. The altar screen is framed horizontally in two parts and into panels by Corinthian pilasters at the corners and doorways. On the exterior, the lower zone of the frieze is filled with acanthus scrolls filled by small animals and birds. Above this, on the east and west ends are allegorical panels flanking the doorways, which depict allegorical or mythological scenes connected to Roman traditions, and associated with the themes of peace and piety.
The eastern and western walls each contain two panels, one well preserved and one represented only in fragments. The eastern wall contains a badly preserved scene which has been interpreted as a representation of a female warrior, possibly Roma, but this reconstruction is based on numismatic evidence and is highly hypothetical. The other panel is better preserved. It represents a woman with twins on her lap, whom scholars have variously identified with the goddess Italia, Tellus, Venus, and Peace, among others. The western wall also contains two panels. The first one seems to refer to the moment when Romulus and Remus were discovered by Faustulus the shepherd, with Mars overseeing the scene. The other one depicts the sacrifice of a pig, and it has been connected to the moment when Aeneas, having recently arrived in Italy, sacrificed a sow and her piglets to Juno, an episode described by Vergil. Other scholars, however, have interpreted the scene in reference to Numa Pompilius, the Roman king associated with Peace.
The northern wall depicts numerous figures: lictors, priests from various colleges, as well as members of the imperial family. A veiled female character may represent Octavia Minor. On the same wall, one may also identify Marcella, a daughter of Octavia, Iullus Antonius, a son of Mark Antony, and two boys and a girl of the imperial family. Gaius seems to have been present as well.
The southern wall is decorated with other figures, including Augustus, Agrippa, Tiberius, Julia, Antonia, Drusus, Germanicus (as a child), but their identification is debated. It seems that the last family depicted on the wall is that of Gnaeus Domitius Ahenobarbus, the father of Nero.
The upper part of the altar is decorated with garlands of fruits and leaves suspended between bucrania, or decorations shaped as oxen’s skulls, from fluttering ribbons. The loops made by the garlands are filled with free-floating paterae, or metal libation bowls. The general impression that emanates from such a decoration is that of abundance and piety.
11.6 m by 10.6 m by 3.6 m
The Ara Pacis had a civic ritual function, but also forwarded Augustus's imperial ideology, especially the celebration of the gens Iulia and the idea of dynastic succession.
The monument is inspired by the classical Altar of the Twelve Gods in the Athenian Agora. The dimensions are the same, and the contrast with the huge dimensions of the Altar of Zeus at Pergamon is evident. Augustus once more followed the rules of classicism. As a matter of fact, the small scale of the architecture of fifth century Athens was more congenial to the Roman leader, as primus inter pares, than the huge altar built to celebrate the glories of an absolute Hellenistic monarch. Thus, the choice of an architectural model which originated in Classical Athens, and not in the Hellenistic East, suggests that Augustus wished to be portrayed, first and foremost, as the first man of Rome, the first of its citizens, emphasizing his auctoritas, or moral authority, as the main source of his power. In fact, Augustus’s legal position followed strictly the patrician-senatorial tradition of political power of the optimates, or the nobility, to which Augustus belong. Therefore, while presenting himself as the Restorer of the Republic, Augustus looked back to Classical Athens, finding his model in the figure of Pericles, and not in the contemporary Hellenistic rulers (Zanker, The Power of Images in the Age of Augustus, p. 302-306). As Pericles was in fact the supreme ruler of democratic Athens, Augustus was the supreme ruler of the Roman Republic. The sentence of Thucydides which defines Pericles’s position in Athens could be applied to Augustus in Rome, “There was in Athens a democracy, but in fact the power was in the hands of the first of the citizens" (Thucidydes, The Peloponnesian War II.65.9).
The frieze probably depicts the religious ceremony performed in 13 BCE, and it mirrors one of the main Augustan ideals, pietas or religious piety. In fact pietas, together with virtus, or bravery, clementia, or clemency, iustitia, or justice, was one of the four virtues mentioned on the Clipaeus Virtutis, awarded by the Senate to Augustus in 27 BCE. Paul Zanker emphasizes the fact that the princeps was by himself the first and most effective example of devotion: he was a member of the most important priestly college, and was in fact the pontifex maximus, or the high priest of Roman state religion, already long before he held the position of pontifex maximus in 12 BCE.
The Altar was dedicated to Pax, the Roman goddess of peace. There was a festival in her honor on January 3. Pax, or Peace, was one of the most important benefits that a ruler could bestow on his subjects. Carlos Noreña emphasizes that pax had for the Romans a dual meaning. Pax could stand for the absence of civil wars as well as for the Pax Romana, or the peace imposed by the Romans on conquered peoples, both provincials and the subjects of client kings allies of Rome. As Carlos Noreña rightly writes: “Augustus highlights the foundation of military might upon which the Pax Romana rested, as Pax is unambiguously presented as the result of military victory: ‘peace gained though military victories’ (Augustus, Res Gestae 13). Similarly, the Ara Pacis Augustae was a monument not to domestic concord but to imperialism and the military pacification of the oikoumenē" (Noreña, Imperial Ideals, p. 128).
Finally, the reliefs depicted on the western wall, illustrating the arrival of Aeneas in Italy (probably) and the birth of Romulus and Remus, emphasize the close bond between Augustus and the gens Iulia, which claimed to descend from Aeneas, the son of Venus. In 2 BCE, seven years later, the senate bestowed upon Augustus the title of pater patriae, “father of the fatherland,” which according to the legend, had been conferred to Romulus, the founder of Rome. The Ara Pacis is primarily the celebration of the ruler, together with his extended family, which probably included his wife, Livia, together with her sons Drusus and Tiberius, and of course, Marcus Vipsanius Agrippa, Augustus’s co-regent (even if they cannot be identified with absolute certainty). The ideological message of the procession is clear: the moral welfare of the Roman state is tied to the prosperity and the future of the Julian family.