1911 Encyclopædia Britannica/Virbius
VIRBIUS, an old Italian divinity, associated with the worship of Diana at Aricia (see Diana). Under Greek influence, he was identified with Hippolytus (q.v.), who after he had been trampled to death by the horses of Poseidon was restored to life by Asclepius and removed by Artemis to the grove at Aricia, which horses were not allowed to enter. Virbius was the oldest priest of Diana, the first "king of the grove" (Rex Nemorensis). He is said to have established the rule that any candidate for the office should meet and slay in single combat its holder at the time, who always went about armed with a drawn sword in anticipation of the struggle. Candidates had further to be fugitives (probably slaves), and as a preliminary had to break off a bough from a specified tree. By the eponymous nymph Aricia, Virbius had a son of the same name, who fought on the side of the Rutulian Turnus against Aeneas. J. G. Frazer formerly held Virbius to be a wood and tree spirit, to whom horses, in which form tree spirits were often represented, were offered in sacrifice. His identification with Hippolytus and the manner of the latter's death would explain the exclusion of horses from his grove. This spirit might easily be confounded with the sun, whose power was supposed to be stored up in the warmth-giving tree. Sauer (in Roscher's Lexikon) also identifies Hippolytus with the "health-giving sun," and Virbius with a healing god akin to Asclepius. Frazer's latest view is that he is the old cult associate of Diana of Aricia (to whom he is related as Attis to Cybele or Adonis to Venus), the mythical predecessor or archetype of the kings of the grove. This grove was probably an oak grove, and the oak being sacred to Jupiter, the king of the grove (and consequently Virbius) was a local form of Jupiter. A. B. Cook suggests that he may be the god of the stream of Nemi.
See Virgil, Aen. vii. 761 and Servius, ad loc. Ovid, Fasti, iii. 265, vi. 737, Melam. xv . 497; Suetonius, Caligula, 35; Strabo, V. p . 239; G. Wissowa, Religion und Kultus der Romer (1902), according to whom Virbius was a divinity who assisted at childbirth (cp. the nixi di); J. G. Frazer, Golden Bough (1900), ii. p. 313, iii. p. 456, and Early History of the Kingship (1905), pp. 24, 281; A. B. Cook in Classical Review, xvi. p . 372.