Numa tradition
The ancients considered the Numa tradition to be the oldest, purest, and most reverent form of the religio Romana. Numa received this tradition from the Gods, through Egeria in the sacred grove of Carmentis, and through direct contact with the highest Gods. Everyone understood that the Numa tradition forbids the use of blood sacrifices. As Plutarch explained, "they were not celebrated with effusion of blood, but consisted of flour, wine, and the least costly offerings." "The Gods," said Varro, "do not desire blood sacrifice." Only latter were immolationes introduced.
"Formerly what served to reconcile Gods and men was spelt and pure salt's glistening grain. ... A man was wealthy if he could add violets to crowns fashioned from meadow flowers; the knife which eviscerates a pole-axed bull had no role in the sacred rites. Ceres first delighted in a greedy sow's blood (Ovid Fasti 1.337-49)."