Vendryes, Joseph (1958). Études celtiques (in French). Les Belles Lettres.
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Servius' commentary to Aeneid, XI. 785 "Mount Soracte is located in the territory of the Hirpini next to Via Flaminia. It was on this mountain that a sacrifice to Dis Pater was once performed – because it is devoted to chthonic deities – as wolves suddenly appeared and plundered the entrails from the ire. The shepherds chased the wolves for a long time, until they arrived at a cave emanating pestilential gases that killed people standing nearby. The reason for the emergence of this plague was that they had chased the wolves. They received a message that they could calm it down by imitating wolves; that means, living by plundering. They did so, and since then these people have been called Hirpi Sorani."