Salvete omnes

Technically there were never any human sacrifices performed in Rome itself. The exceptional instance, or possible two instances, where the paired Gauls and Greeks were buried took place outside the pomerium. It appears that some of the burials of Vestal Virgins may in fact have been ordered as a human sacrifices. Tacitus implies as much in his description of one ordered by Domitian and there is another instance where the same may have been true. These too were performed outside the City proper.

The Argei, or puppets that Marco mentioned, have been interpreted as substitutes for human sacrifices once performed in a very ancient rite during Rome's barabaric period. That is, it is associated with a period prior to Numa Pompilius establishing the religio Romana. The puppets hung in trees at the feriae Latinae have been interpreted in the same manner. I do not think that was really the case. Bronze figurines have been found at different sites. The most famous I suppose are those that were found on the Capitoline Hill. Recently I saw a collection of such bronze votives at the U. of Penn. They reminded me of the petroglyphs in the Val Camonica where the human figures clearly did not represent human sacrifices. Rather the human figures, painted over one another over an extended period of time, seem to represent worshippers in prayer. The votives, and the puppets I suspect, are related to the terracotta votives of brides, mother and child figurines, and figurines of couples with a child that were found at such places as the sanctuary of Diana Nemorensis at Aricia. Perhaps related, too, are the anatomical votives found at the sanctuaries of healing deities, primarily in the fourth to mid-third centuries BCE. These were probably accompanied by thanksgivings, but represent the worshipper who offered them rather than represent any substitute for a human sacrifice. OTOH some votives are of animals. Generally we interpret such animal representations as symbolizing animal sacrifices, or even that the figurines were substituted for animal sacrifices. That may not be the case, any more than for human figurines. It could be that the figure of a pig or cow was offered in thanks on behalf of the animals whose health was protected by the Gods.

Most sources agree that Numa Pompilius prohibited the use of any blood sacrifices, human or animal. The sanctuary of Carmena, where Numa supposedly met with Egeria, prohibited all blood sacrifices. There were some other sites as well that had temple rules prohibiting the use of any blood sacrifices, and generally such sites are identified as very early sanctuaries. This raises a question, for if true, then the introduction of animal sacrifices at Rome would be later than Numa. Perhaps Ovid offers a hint as to when where he said in the Fasti and in the Metamorphoses that Ceres was the first to demand a blood sacrifice. Could that mean that blood sacrifices began at Rome with the Aventine cultus of the Temple of Ceres, Liber, and Libera in 493 BCE? At any rate, by the Late Republic there was a strong tradition that blood sacrifices were not originally part of the religio Romana and that they should be done away with in order to return to a purer and more devout form of the religio. Varro, as one example, wrote that "the Gods do not want blood sacrifices, Their images even less."

However there is clear evidence that human sacrifice did once occur at Rome. In the 1860's four small pillars were found that were buried beneath the pomerium during the time of Augustus. The pillars were inscribed and alluded to their burial as a substitute for human sacrifices when expanding and rededicating the pomerium. A tradition existed that the death of Remus was in fact performed as a voluntary human sacrifice, one that sanctified the original pomerium. Later when the pomerium was expanded a sacrifice of four humans was performed at the former pomerium near where Remus traditionally had been slain. The Augustan pillars commemorated these earlier sacrifices. Then in the late 1990's Carandini uncovered the four original graves of a man, a youth, a child and a woman, with two laid inside and two outside the pomerium. They were located where Remus had supposedly been slain, and were laid out in a manner that suggests they were placed at the entrance into the pomerium. There remains some question as to when these burials were actually made. The fourth century I think is a reasonable possibility, when Rome was refounded in the wake of the Gallic sack, the so-called Servian Wall was erected, and the pomerium rededicated. This was a time when the oral tradition of the pontifices, supposedly extending back to Numa Pompilius, was written down and when the Postumian law on sacrifices was reintroduced. Under those unusual circumstances, the tribunes with consular powers "consulted the Senate before everything else on questions of religious observances" and "such as dealt with sacred rites were kept private by the pontifices"(Livy 6.1.9-12). Might this then refer to the Romans reinstituting ancient rites to renew their devastated City, even then resorting to a human sacrifice to resanctify the defiled pomerium?