DEVOTIO, RITE OF. – It was a particular kind of *votum* in which an individual vowed himself and immolated himself beforehand to the infernal deities in order to obtain, through the sacrifice of himself, the victory of his own side and the defeat of the enemy. The original meaning appears from the *devotio* of Decius Mus the Elder, at the foot of Vesuvius in 340 B.C.; when victory was in danger, he threw himself into the fray, invoking the tutelary gods of the fatherland so that they might save the Roman army and annihilate the enemy with him.
The *devotio* differs from the *votum* in that in the latter the human obligation is conditional upon the deity’s granting the prayer, whereas in the *devotio* the sacrifice precedes and binds the obligation of the gods. Livy (VIII, 9, 6 ff.) has transmitted the typical formula, which reflects this conception of the *devotio*; the formula was suggested and prepared by the pontifex.
Alongside the *devotio* of public value there were private *devotiones* that anyone could perform, substituting himself for another’s benefit, as in the *devotiones pro salute principis*, frequent during the Roman Empire. As for the particular formulas of *devotio* against individuals, V. DEFISSIONE.