What is "devotio"

In ancient Roman religion, the devotio was an extreme form of votum (an offering in fulfillment of an advance promise) in which a Roman general vowed to sacrifice his own life in battle along with the enemy to chthonic gods in exchange for a victory. The most extended description of the ritual is given by the Augustan historian Livy, regarding the self-sacrifice of Decius Mus. The English word "devotion" derives from the Latin.

Devotio may be a form of consecratio, a ritual by means of which something was consecrated to the gods. The devotio has sometimes been interpreted in light of human sacrifice in ancient Rome, and Walter Burkert saw it as a form of scapegoat or pharmakos ritual. By the 1st century BC, devotio could mean more generally "any prayer or ritual that consigned some person or thing to the gods of the underworld for destruction."