The pignora imperii ("pledges of rule") were objects that were supposed to guarantee the continued imperium of Ancient Rome.
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, the second king of Rome.
[1] 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.
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.
[3] The 4th-century scholar Servius notes in his commentary to Vergil's Aeneid that "there were seven tokens (pignora) which maintain Roman rule (imperium Romanum)," and gives the following list:[4] Classicist 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.