Salvete
Here are prayers found among various Latin authors of the Imperial Period
Arnobius (c. 295 CE)
Adversus Nationes III 43
Come, Dii Penates, come Apollo and Neptune and all You Gods, and by Your powers may You mercifully turn aside this ill disease that violently twists, scorches and burns our city with fever.
Titus Calpurnius Siculus (mid first century CE)
Eclogae II 52
O if only someone would carry off a god to Crocalen.
Claudius Claudianus (c. 370-408 CE)
In Rufinum 1.334-9:
Mars, whether you rush down from the cloud-capped Balkans, whether on the frosty white mountains of Thrace, whether stirring on Monte Santo in Macedonia with the black boots of soldiers stationed on all the lands they hold, to make ready with me, and defend your Thrace, if it is made happy, the campaign coming into glory, the sacred oak will be dressed with an offering of spolia.
In Olybii et Probini fratres Consules Panegyricus
1-7.
O Sol, whose light embraces the world, you orbit inexhaustible, forever returning, your face glowing on each day, your horses harnessed as a team to drive your chariot, with manes braided pleasantly they rise high, passing over rose-red clouds as you rein their frothing fires. Already yet another year begins, measured by the footsteps of brothers, who as new consuls gladly offer their prayers and vows.
71-2:
To you I pray, Apollo of Mount Parnassus, that you may inspire the pythia with so important knowledge, as to whom between us, O God, you will reward with authority.
Aulus Gellius (c. 130-170 CE)
Noctes Atticae XIII.23.13:
When Titus Tatius spoke in favor of peace, among his words was this prayer, "Neria, wife of Mars, I appeal to you, give peace. May you use your own favored position with your husband; counsel Him to partake in this plan. In the same way as we reconcile ourselves to those who carried off our daughters, may you now join with Him for all times in favoring His."
Grattius
Cynegetica 437-42
Holy Vulcan, foremost of this place, to You we pray. Grant peace to the exhausted fire brigades and to those who service the fountains. If none are harmed so very much, if the flames You permit to assault only a few deplorable souls, Holy One, then at each of your altars they will sing your praises, three times, three times they will pour libations and make thick with incense Your altar fires piled high with fruitful boughs.
Juvenal (c. 47-130 CE)
Satires IV.34-5
Muses, speak forth, you maidens of Pieria, and let it profit me that I have called you maidens.
VII 207-8
Grant, O Gods, that the earth may lie soft and light upon the shades of our forefathers, may the sweet scented crocus and perpetual spring bloom over their ashes.
X 185
Grant me a great length of life, O Jupiter, give to me many years.
M. Manilius
Astronomicon 1.30ff
Mercurius Cyllenius, principle author of all sacred knowledge, at times within Heaven, at other times travelling within the starry signs to open the celestial paths to the highest parts above and the lowest paths beneath the earth. You stitch together the stars in the empty void of space into constellations, name them and determine their course; may it have been for us to reverently use the greater powers of the universe that You make, pondering them, not in all matters, but in the potential of things in themselves, and to learn of the divine plan set for the greatest nations.
Scriptores Historiae Augustae (Late third, early fourth centuries CE)
Vita Probi c. 12.7
Jupiter Optimus Maximus, Juno Regina, and You virtuous dancer, Minerva, Concordia of the bereaved, Victoria of the Romans, grant this meeting of the Senate of the Roman people, grant these Roman soldiers, and those soldiers of our allies and of friendly foreign nations as well, that they will serve as he commands.
Tacitus (c. 54-117 CE)
Annales XVI. 35
Thrasea speaks to his son Helvidius after he has opened the veins of his wrists: "We pour out a libation to Jupiter the Liberator. Observe, discover, and may the Gods avert the omen from you, my son, but you are born into a time when it is expedient to fortify your spirit with examples of courage and firmness of mind in the face of adversity."
Historiae IV 58
I implore and entreat you, Jupiter Optimus Maximus, to whom for eight hundred and twenty years we have paid the highest honors in so many triumphs, and I pray and venerate You Quirinus, Father of the City of Rome, if You would not be pleased to see this camp remain pure, preserved and inviolate under my command, may You at least not allow it to be polluted and defiled by a Tutor and a Calssicus. Grant that the soldiers of Rome may either be innocent of a crime, or at least may they be granted a speedy repentance without punishment.
Valerius Cato
Lydia 41-44
Your love, O Moon, is with you; why then am I not also with mine? O Moon, you know what grief is; pity one who grieves. (Endymion) who caresses You, O Phoebus, celebrates love with a laurel, and what procession has not told the story to the Gods, or when has fame not told it to the forest?
Valerius Maximus (c. 32 CE)
VI 1, praef. De Pudicitia
From whence should I invoke You, Pudicitia, mainstay of both men and women? You inhabit the hearth that ancient religion consecrated to Vesta. You care over the wedding bed of Juno Capitolina. At the height of the Palatine, that most holy of residences, You remain as one of the household gods of Augustus Caesar and by his daughter Julia?s wedding bed. You preside over the insignia of boyhood, and in respect for Your divine power is the flower of youth protected. You safeguard the maiden and by You is a matron?s stola judged. Come, therefore, and recognize what things You yourself have ordained.
8.1.5 (absol.)
(Vestal Virgin Tuccia prayed for proof of her innocence:) O Vesta, if I have always brought pure hands to your secret services, make it so now that with this sieve I shall be able to draw water from the Tiber and bring it to Your temple.
Vellius Paterculus (19 BCE - c. 39 CE)
II 131.1
Jupiter Capitolinus, Mars Gradivus called progenitor and aide of the Romans, Vesta, perpetual guardian of fire, and whatever divine powers in this greatness of Roman sovereignty, the largest empire on earth, exulted to the highest dignity, to You the public voice calls to witness and to pray: guard, preserve, and protect this state, this peace, this prince, and those who succeed to the Senate, by their long standing, determined worthy to consider the most grave matters among mortals.