The evocatio of Carthage
The evocatio is the most peculiar rite in Roman religion. Before taking a city, the commander summoned its tutelary gods out of it and invited them to move to Rome. Not to defeat the enemy's deity, but to recruit it.
Si deus si dea est — whether god or goddess. The deity's sex is not stated, nor its name: "and you above all, whoever you are, who have taken up the guardianship of this city". The Romans knew perfectly well who guarded Carthage, but did not pronounce the name — a named protector was held to be removable, which is why the secret name of Rome's own guardian was never divulged.
What is offered is not submission but terms of relocation: leave their places and shrines, cast fear and forgetfulness upon them, come to me and to mine, and let our places and temples be more pleasing to you. It is a contract of transfer of service, with a promise of better keep.
The rite was not a figure of speech. Juno of Veii was called out of Veii and given a temple on the Aventine; Juno Caelestis, the protectress of Carthage, received a sanctuary in Rome. Rome took defeated gods into its household, and that probably explains more about it than any other of its practices.
The evocatio was followed by the devotio of the doomed city (macrobius-devotio-001), and in that order: first get the gods out, then destroy. While the gods were still inside, the city was not touched.