Though documented, human sacrifice was rare in Rome during the historical period. Livy and Plutarch both considered it alien to Roman tradition. This aversion is asserted also in an aetiological myth about sacrifice in which Numa, second king of Rome, negotiates with Jupiter to replace the requested human victims with vegetables. In the first century BC, human sacrifice survived perhaps only as travesty or accusation. Julius Caesar was accused — rather vaguely — of sacrificing two mutinous soldiers in the Campus Martius. On the anniversary of Caesar's death in 40 BC, after achieving a victory at the siege of Perugia, the future Augustus executed 300 senators and knights who had fought against him under Lucius Antonius. Lucius was spared. Perceptions of the clemency of Augustus on this occasion vary wildly. Both Suetonius and Cassius Dio characterize the slaughter as a sacrifice, noting that it occurred on the Ides of March at the altar to the "divus Julius", the victor's newly deified adoptive father. It can be difficult to discern whether such an act was intended to be a genuine sacrifice, or only to evoke a sacral aura of dread in the minds of observers and those to whom it would be reported. Moreover, these two incidents took place within parameters of victory and punishment in a military setting, outside the civil and religious realm of Rome.