Sacramentum (oath)

Sacramentum (oath)

In ancient Roman religion and law, the sacramentum was an oath or vow that rendered the swearer sacer, "given to the gods," in the negative sense if he violated it. Sacramentum also referred to a thing that was pledged as a sacred bond, and consequently forfeit if the oath were violated. Both instances imply an underlying sacratio, act of consecration.

The sacramentum differs from iusiurandum, which is more common in legal application, as for instance swearing an oath in court. A sacramentum establishes a direct relation between the person swearing (or the thing pledged in the swearing of the oath) and the gods; the iusiurandum is an oath of good faith within the human community that is in accordance with ius as witnessed by the gods.

Sacramentum is the origin of the English word "sacrament", a transition in meaning pointed to by Apuleius's use of the word to refer to religious initiation.