Roman sacrificial practices were not functionally different from Greek, although the Roman rite was distinguishable from the Greek and Etruscan. As in the Greek world, sacrifice was the central ritual of religion. The expression rem dīvīnam facerē, ‘to make a thing sacred’, shows that sacrifice was an act of transfer of ownership. On its own or part of larger celebrations, the typical sacrifice embraced four phases: the praefātio, the immolātiō, the slaughtering, and the banquet.1. After the purification (see lustration) of the participants and of the victims (always domestic animals) chosen in accordance with the divinity's function and the context, a procession led them to the altar of the divinity. There the presiding figure celebrated the praefatio (‘preface’) on a portable hearth set up beside the sacrificial altar. This rite consisted of offering incense and wine, and was the equivalent of a solemn salutation affirming the superiority of the gods. At the same time this rite opened a ritual space and announced what was to follow.2. The second stage of the sacrifice was the immolatio. The presiding figure poured wine on the victim's brow, sprinkled its back with salted meal (mola salsa, whence immolārě), doubtless prepared by the Vestals, and finally passed a sacrificial knife over the victim's spine. Acc. to the prayer spoken during this rite, immolation transferred the victim from human possession to the divine.3. Once this transfer was effected, the sacrificers felled the victim, butchered it, and opened the corpse, now on its back. The presiding figure then performed the inspection of the exta (vital organs: the peritoneum, liver, gall bladder, lungs, and, from the beginning of the 3rd cent. bc, the heart), to decide if they were in the good shape which would signal the god's acceptance of the sacrifice. If the victim was unacceptable, the sacrifice had to begin again.4. The banquet comprised two phases. Once acceptance was obtained, the sacrificers beheaded the victim, set aside the exta, and prepared them for offering: the exta of bovines were boiled in cooking‐pots, those of ovines and porcines were grilled on spits. This cooking done, the exta were offered to the god, i.e. burnt, basted with mola salsa and wine. This was done on the altar if celestial gods were in question; offerings to aquatic gods were thrown into the water, those for chthonian gods were placed on the ground or in ditches. Offerings for the di manes were made on a pyre resting on the ground. When the offering to the god had been consumed, the rest of the victim was seized by the presiding figure, no doubt by imposition of the hand, and thus rendered fit for human consumption. In principle all sacrifices, except those addressed to gods of the Underworld, were followed by a sacrificial banquet. Sometimes the banquet was celebrated (doubtless on behalf of all) by just the immediate participants and their helpers, along with those possessing privileges in a particular sanctuary (e.g. the pipe‐players at the temple of Jupiter); sometimes the banquet united the chief sections of society (e.g. the Roman élite for the epulum Iovis; see septemviri epulones); sometimes the meat was sold in butchers' shops (i.e. it was accessible to all); sometimes, finally, it was eaten at great communal banquets, ultimately financed by benefactors. At the Ara Maxima of Hercules, sacrificial meat had to be eaten or burnt before nightfall, a requirement giving rise to a very generous form of sacrificial banquet.Communal sacrifices were celebrated by those who exercised power in the community in question: the paterfamilias, magistrates and priests, and the presidents of clubs. Women could not normally sacrifice on behalf of the whole community. Many sacrifices were part of much larger celebrations, and in certain cases the sacrifices themselves were celebrated in more spectacular fashion (e.g. at the lectisternium). Occasions for sacrifice were innumerable, from regular acts of homage shaped by sacred calendars and the ritual obligations of the city and its constituent associations to thank‐offerings or contractual sacrifices. Faults and involuntary oversights committed in the celebration of the cult, or the involuntary deterioration of the patrimony of the gods, were expiated by piācula, sacrifices the purpose of which was to present excuses for past or imminent action (e.g. maintenance works in a sanctuary).