As Augustus returned to Rome in 13 BC, the Senate passed a constitutio to build in his honor a lasting altar of peace, the Ara Pacis Augustae, to signal with a major ceremony the new peace all over the Roman world, Gibbon’s Pax Romana. As we know from Ovid Fast. 1. 709–714, 3. 881–882, the Ara Pacis was the site of two annual sacrifices (on 30 Jan. and 30 March) to Pax, an innovation of the Augustan Age, for formerly Pax had been a minor goddess without a temple. The Augustan regime elevated a new form of Pax as a religious cult and made it acceptable to the Roman people, who had regarded Pax as the phenomenon of a foreign power too beaten down to resist Roman arms any longer and had no use for pacifism (in the modern sense), which would be seen only as cowardly in their dangerous world.
Augustus had started this process, perhaps not intentionally, back when he closed the Gates of Janus in 29. By bringing together Greco-Roman elements of Pax with Jupiter and Janus, he was able to forge a new religious cult to Pax Augusta that could appeal to the average Roman by its promise of prosperity and the absence of civil war. Foreign war was perfectly acceptable and not incompatible with this cult, but the emphasis was on domestic harmony and old traditional religious practices, even if the average listener could not understand some of these obligatory, archaic chants. For this reason, the third closing of the Gates of Janus very likely accompanied one of the Ara Pacis ceremonies.
Augustus also built on precedents from his divine father Julius, who had founded the towns Forum Iulii Pacatum (Fréjus, France) and Pax Iulia (Beja, Portugal) and issued Pax imagery on coinage to gain the moral high ground during the civil war. Augustus went one step further with larger sets of Pax coin issues to tell the people that he, not Antony, was trying to maintain peace when Cleopatra wanted war, and then a sequel after Actium that demonstrated his ability to prevail and restore order. The image of Pax Augusta evolved as it developed, but the epitome is the goddess we see on the East side of the Ara Pacis, surrounded by fertility and prosperity, in a state of security. Rome too would enjoy the same benefits.
In 13 BC, Augustus returned to Rome from a lengthy tour of the western provinces, just as Agrippa returned from the East. All conditions had been readied to present to the Roman people the establishment of Agrippa as the new partner of Augustus’ labours after a multi-year build up, culminating in the Ara Pacis ceremony at which Agrippa co-presided. However, to those watching the political slogans and headlines of the Roman mint, the Ara Pacis ceremony and Agrippa’s prominent role therein did not bring news, for the coinage of 13 boldly proclaims Agrippa as if he were second princeps by advertizing his enhanced status and by highlighting his accomplishments beyond the level ever provided for any of Augustus’ other colleagues, including his eventual successor, Tiberius (whose own enhancement of powers after AD 4 was modeled upon the precedent of Agrippa).
The coinage of 13 BC represents a break from the recent general pattern in that it broke up Augustus’ quasi-regal domination of the mint, and it sent out two simultaneous and compatible messages. Firstly, and more specifically, the imagery informed the Roman public as do newspaper headlines today of the elevation of Agrippa as Augustus’ legal equal, showing that Rome was no monarchy. The Roman mint alternated between standard issues for certain messages and new images for others, including escalation of the status of Agrippa.
The year 13 provided several occasions to raise the status of Agrippa, a novus homo. Agrippa was offered a third triumph, which he again refused. He received a new priesthood(s). His tribunician power was renewed for five years, as was that of Augustus. And at the Ara Pacis ceremony, Agrippa shared equal credit for pacifying the Empire in a ceremony that may have included closing the Gates of Janus. Much of this information comes to us not just from textual evidence, but also the archeological record. The coinage of 13 informs us of the regime’s official statements and the Ara Pacis itself shows the veiled Augustus at the head of the Pontifical College and the veiled Agrippa completing the Pontifical College and starting the imperial family as a demonstration of his integral role in the state, although tragically his life would end before the Ara Pacis was completed, leaving it to be a monument of a vision of the future Augustus was never able to achieve.
The Roman father and son of the same name, P. Decius Mus, became paragon heroes by deliberately giving their lives in battle that Rome might win over a fierce enemy. Both engaged in a special ritual called devotio (from which our word “devotion” derives) to offer themselves to the gods of the Underworld, with whom regular people have very little interaction and to whom they rarely sacrifice. While the Mus family is the most famous for this act, it turns out the willingness to sacrifice oneself for Rome frequently occurs within stories of great patriots, including the story of Horatius Cocles, Mettius Curtius, Atilius Regulus, and even the traitors Coriolanus and Tarpeia.
Romans regarded self-sacrifice as a very high, noble endeavor, whereas they loathed and persecuted practitioners of human sacrifice. It is therefore quite amazing to read that the Romans thrice engaged in state-sponsored human sacrifice, a fact they rarely mention and generally forget. The most famous enemy practitioners of human sacrifice were the Druids, whom the Romans massacred on Mona Island on Midsummer Night's Eve, but the Carthaginians, the Germans, the Celts, and the Thracians all infamously practiced human sacrifice. To Romans, the act of human sacrifice falls just short of cannibalism in the spectrum of forbidden practices, and was an accusation occasionally thrown against an enemy to claim they are totally barbaric. On the other hand, Romans recognized their own who committed acts of self-sacrifice for the good of the society, as heroes.
There can be no better patriot than he who gives his life to save his country. Often the stories of their heroism have been exaggerated or sanitized. These acts of heroism often turn out to be acts of human sacrifice, supposedly a crime. It turns out that Romans have a strong legacy of practicing human sacrifice that lasts into the historic era, despite their alleged opposition to it. Numerous sources relate one story each. Collecting them all makes it impossible to deny the longevity of human sacrifice in Rome, although most Romans under the emperors were probably unaware of it. The paradox of condemning but still practicing human sacrifice demonstrates the nature of Roman religion, where do ut des plays a crucial role in standard sacrifice as well as in unpleasant acts like human sacrifice. Devotio was an inverted form of sacrifice, precisely because it was an offering to the gods of the Underworld, rather than to Jupiter or the Parcae. Romans may have forsaken devotio, but they continued to practice human sacrifice far longer than most of us have suspected, if one widens the current narrow definition of human sacrifice to include events where a life is taken in order to bring about a better future for the commonwealth, appease the gods, or ensure a Roman victory in battle.