The Romans had strict beliefs against the practice of human sacrifice. It was seen as the practice of uncivilized people and that many of their rituals derived from past rituals that may have once involved human sacrifices. This included the ritual of the Argei in which straw figures were thrown into the Tiber river, it was suggested this may have once involved living people. The Romans would then use propaganda of human sacrifice to justify barbaric practices against their enemies. This included their propaganda against the Celts which led to them brutally killing captured Celts.
Despite their feelings against human sacrifice, the Romans were guilty of human sacrifice as well. However, the Romans did not view their human sacrifices as being the same because it was only part of very specific rituals. If a Vestal Virgin was found to be unchaste she would be buried alive. A special chamber was built to seal away any unchaste Vestal Virgin until she starved. The sacrifice was seen as a necessary means to please the Gods for the infraction of the Vestal Virgin.
The chosen method of sacrifice for the Vestal Virgin was in order to preserve the body even in punishment. It was believed that the chasteness of the Vestal Virgins was necessary in order to protect the city. But it was not just the Vestal Virgins that could be subjected to human sacrifice. Hermaphroditic children were also sacrificed by drowning. The sacrifice of children largely came from the belief that they were evil or damaged.
There were also some accounts of sacrifice of enemies or captured peoples. The Celts for example were reported to have died brutally with their hands and feet severed and then left to bleed to death. Captured enemy leaders would be kept until a Roman victory at which point they would be killed. The Romans did not see this as a form of human sacrifice nor were gladiatorial fights considered to be sacrifices. By refusing to acknowledge these as human sacrifices the Romans were able to keep distancing themselves from their “uncivilized” enemies.