The pignora imperii ("pledges of rule") were objects that were supposed to guarantee the continued imperium or rule of Ancient Rome. One late source lists seven. The sacred tokens most commonly regarded as such were the Palladium, the wooden image of Minerva (Greek Athena) that the Romans claimed had been rescued from the fall of Troy and was in the keeping of the Vestals; the sacred fire of Vesta tended by the Vestals, which was never allowed to go out; and the ancilia, the twelve shields of Mars wielded by his priests the Salii in their processions, dating to the time of Numa Pompilius, second king of Rome.
In the later Roman Empire, the maintenance of the Altar of Victory in the Curia took on a similar symbolic value for those such as Symmachus who were trying to preserve Rome's religious traditions in the face of Christian hegemony. The extinguishing of the fire of Vesta by the Christian emperor Theodosius I is one of the events that mark the abolition of Rome's ancestral religion and the imposition of Christianity as a state religion that excluded all others.
In late antiquity, some narratives of the founding of Constantinople claim that Constantine I, the first emperor to convert to Christianity, transferred the pignora imperii to the new capital. Though the historicity of this transferral may be in doubt, the claim indicates the symbolic value of the tokens.
- the stone of the Mother of the Gods (Cybele);
- the terracotta four-horse chariot brought from Veii, supposed to have been commissioned by the last king of Rome Tarqinius Superbus, which was displayed on the roof of the Temple of Jupiter Optimus Maximus on the Capitoline;
- the ashes of Orestes, supposedly kept at the same temple;
- the scepter of Priam, brought to Rome by Aeneas;
- the veil of Ilione, daughter of Priam, another Trojan token attributed to Aeneas;
- the Palladium;
- the ancilia or sacred shields given to Numa.
Alan Cameron notes that three of these supposed tokens were fictional (the ashes, scepter, and veil) and are not named in any other sources as sacred guarantors of Rome. The other four objects were widely attested in Latin literature, but have left no archaeological trace.
- Ovid, Fasti 3.422; Geraldine Herbert-Brown, Ovid and the Fasti: An Historical Study (Oxford University Press, 1994), pp. 76–77; R. Joy Littlewood, A Commentary on Ovid's Fasti, Book 6 (Oxford University Press, 2006) pp. 132–135; Robert Turcan, The Gods of Ancient Rome (Routledge, 2001; originally published in French 1998), p. 59; Andreas Hartmann, Zwischen Relikt Und Reliquie: Objektbezogene Erinnerungspraktiken in Antiken Gesellschaften (Verlag Antike, 2010), pp. 545–565.
- Sabine MacCormack, The Shadows of Poetry: Vergil in the Mind of Augustine (University of California Press, 1998), p. 167; Symmachus, Third Relatio 8.
- Clifford Ando, "The Palladium and the Pentateuch: Towards a Sacred Topography of the Later Roman Empire," Phoenix 55 (2001) 369–410, especially pp. 398–399.
- Servius, note to Aeneid 7.188: septem fuerunt pignora, quae imperium Romanum tenent: acus matris deum, quadriga fictilis Veientanorum, cineres Orestis, sceptrum Priami, velum Ilionae, palladium, ancilia.
- The text is vexed at this point; it is assumed that the baetylus transported to Rome with the cult of Cybele and stored in the Palatine Hill Temple of Cybele is meant.
- Vergil, Aeneid I.647-655.
- Alan Cameron, The Last Pagans of Rome (Oxford University Press, 2011), n.p. edition online.
- Cancellieri, Francesco (1842). Le sette cose fatali di Roma antica (Seven things whose loss was Fatal for Ancient Rome, i.e. Pignora Imperii). Rome: L.P. Salvioni.