Imperatores. -After Nero, the Emperors for the most |part| ceased to govern by heritary right. (Spanh. Pr. ii. p. 238). Writing to the governors of provinces theycalled themselves, not Augusti, but Imperatores (ibid. p. 374) -nay, sometimes they even mentioned themselves as of the number of the Senators (ibid. p, 413). -Emperors were called Patres, after the example of Jupiter, as Patres Ausonii, Patres Latii, etc (ibid. p. 450). -Appelations peculiar to the Imperatores Romanorum, and observable on their coins, are Pater Castrorum, Pater Exercituum, which as words denoting the highest rank were accustomed to be exclusively applied to the Augusti, or to their appointed heirs. Moreovera new surname was invented in honour of the Emperors, viz., that of Pater Senatus, which was first concieved by Commodus, called on his silver coin PATER SENATVS; and afterwards by Pupienus and Balbinus, as appears on their coins, inscribed PARES SENATVS. -(Vaillant). -Some Emperors were called Optimi, some Maximi, and others Optimi Maximi, the two being joined as if equalling them with Jupiter himself. (Spanh. Pr. 500-501), -Pii and Felices were also among the titles of honour. And in like manner some were called Orbis Rectores, Restitutores, Locupletatores orbis terrarum -also Pacatores Orbis, Ubique Victores, etc, etc.
The Imperatores Romani had by right no other power in sacerdotal and sacred affairs than that which they derived from holding the highest pontificate (maximus pontificatus), and the Emerors themselves exhibited their testimonies of piety to the Gods, in discharging the offices of pontiffs. For after Tiberius they were admitted to all the functions of the priesthood; and from the very moment of their accession to the empire, they sacrificed bare-headed and covered, and in quality of pontiffs performed sacred rites. The Emperors, on their coins, are represented in the act of sacrificing. We see the contents of the patera poured out by them on the lighted altar; the popa, or priest whose provence it was to slay the victim, standing near it, and ready to perform his office. Amongst the numerous representations of this kind to be found on the Latin Caesarian medals may be mentioned: Caligua sacrificing in front of a temple (see PIETAS), Severus Alexander sacrificing before Jupiter. On coins also of Trajan, Marcus Aurelius, L. Verus, Commodus, Severus, Alexander, Maximinus I, Gordianus Pius, we see some fine sacrificial groups, in which the Emperors are the prominant figures. -See Sacrifices.
Some of the Imperial series bear legends and types which testify the piety or religion of the reigning prince towards the gods, as in the RELIGIO AVG of M. Aurelius and Valerianus; and in the PIETAS AVG of Trajan, Hadrian, Antoninus, M. Aurelius,and others, with an altar, or with the Emperors sacrificing; or with pontifical instruments, or with a temple, or with Piety personified under the figure of a woman, standing with a patera in her hand before an altar; also with the image of Mercury holding his caduceus, and crumena, or purse. -Even the truculent monster Commodus is on one of his coins called AVCTOR PIETAT [is]. -In token of Piety, the temples of the Gods were frequently either erected, or repaired, or dedicated by the Emperors as well as at Rome as in the provinces; a custom which explains why on so many of their coins, we read, AEDES AVG or AED DIVI AVG REST; DEDICATIO AEDIS, and similar inscriptions.