Laudator Temporis Acti

Livy 5.21.1-3 (396 BC; tr. B.O. Foster):

[1] A vast throng went out, and filled the camp. Then the dictator, after taking the auspices, came forth and commanded the troops to arm. [2] "Under thy leadership,” he cried, "Pythian Apollo, and inspired by thy will, I advance to destroy the city of Veii, and to thee I promise a tithe of its spoils. [3] At the same time I beseech thee, Queen Juno, that dwellest now in Veii, to come with us, when we have gotten the victory, to our City—soon to be thine, too—that a temple meet for thy majesty may there receive thee."

[1] ingens profecta multitudo replevit castra. tum dictator auspicato egressus cum edixisset ut arma milites caperent, [2] "tuo ductu" inquit, Pythice Apollo, tuoque numine instinctus pergo ad delendam urbem Veios tibique hinc decimam partem praedae voveo. [3] te simul, Iuno regina, quae nunc Veios colis, precor, ut nos victores in nostram tuamque mox futuram urbem sequare, ubi te dignum amplitudine tua templum accipiat."

This is the earliest known example of evocatio, i.e., "A ritual by which, in the course of war, a Roman general would attempt to deprive the enemy of divine protection, by formally offering their protecting deity a new home and cult at Rome" (Mary Beard, Oxford Classical Dictionary, s.v. evocatio).

See Clifford Ando, The Matter of the Gods: Religion and the Roman Empire (Berkeley: University of California Press, 2008), pp. 128-148. I don't have access to Gabriella Gustafsson, Evocation [sic] Deorum: Historical and Mythical Interpretations of Ritualised Conquests in the Expansion of Ancient Rome (Uppsala: Uppsala University, 2000 = Acta Universitatis Upsaliensis. Historia Religionum, 16).