Plutarch, Numa
Bernadotte Perrin, Ed.

9. To Numa is also ascribed the institution of that order of high priests who are called Pontifices, and he himself is said to have been the first of them. According to some they are called Pontifices because employed in the service of the gods, who are powerful and supreme over all the world; and ‘potens’ is the Roman word for powerful. [2] Others say that the name was meant to distinguish between possible and impossible functions; the lawgiver enjoining upon these priests the performance of such sacred offices only as were possible, and finding no fault with them if any serious obstacle prevented. But most writers give an absurd explanation of the name; Pontifices means, they say, nothing more nor less than bridge-builders, from the sacrifices which they performed at the bridge over the Tiber, sacrifices of the greatest antiquity and the most sacred character; for ‘pons’ is the Latin word for bridge. [3] They say, moreover, that the custody and maintenance of the bridge, like all the other inviolable and ancestral rites, attached to the priesthood, for the Romans held the demolition of the wooden bridge to be not only unlawful, but actually sacrilegious. It is also said that it was built entirely without iron and fastened together with wooden pins in obedience to an oracle. The stone bridge was constructed at a much later period, when Aemilius was quaestor.¹ [4] However, it is said that the wooden bridge also was later than the time of Numa, and was completed by Ancus Marcius, the grandson of Numa by his daughter, when he was king.

The chief of the Pontifices, the Pontifex Maximus, had the duty of expounding and interpreting the divine will, or rather of directing sacred rites, not only being in charge of public ceremonies, but also watching over private sacrifices and preventing any departure from established custom, as well as teaching whatever was requisite for the worship or propitiation of the gods. [5] He was also overseer of the holy virgins called Vestals; for to Numa is ascribed the consecration of the Vestal virgins, and in general the worship and care of the perpetual fire entrusted to their charge. It was either because he thought the nature of fire pure and uncorrupted, and therefore entrusted it to chaste and undefiled persons, or because he thought of it as unfruitful and barren, and therefore associated it with virginity. Since wherever in Greece a perpetual fire is kept, as at Delphi and Athens, it is committed to the charge, not of virgins, but of widows past the age of marriage. [6] And if by any chance it goes out, as at Athens during the tyranny of Aristion² the sacred lamp is said to have been extinguished, and at Delphi when the temple was burned by the Medes, and as during the Mithridatic and the Roman civil wars the altar was demolished and the fire extinguished, then they say it must nor be kindled again from other fire, but made fresh and new, by lighting a pure and unpolluted flame from the rays of the sun. [7] And this they usually effect by means of metallic mirrors, the concavity of which is made to follow the sides of an isosceles rectangular triangle, and which converge from their circumference to a single point in the centre. When, therefore, these are placed opposite the sun, so that its rays, as they fall upon them from all sides, are collected and concentrated at the centre, the air itself is rarefied there, and very light and dry substances placed there quickly blaze up from its resistance, the sun's rays now acquiring the substance and force of fire. [8] Some, moreover, are of the opinion that nothing but this perpetual fire is guarded by the sacred virgins; while some say that certain sacred objects, which none others may behold, are kept in concealment by them. What may lawfully be learned and told about these things, I have written in my Life of Camillus.³