Etrusca Disciplina
Joannes Laurentius Lydus lived in the 6th Century AD. Although the last classical-period writer to have read the books, he is the most specific about his sources. He implies that he read "the texts of the Etruscans"; that is, the Etrusca Disciplina, including the report of the haruspex, Tarchon, who was instructed by Tyrrhenus. Tarchon's work on Tages, he says, is a dialogue in which Tarchon asks Tages questions in "the ordinary language of the Italians". This is presumably Vulgar Latin, as Lydus cannot mean any early Italic dialect. Tages' recorded response is "in ancient letters", presumably in the Etruscan language. Lydus says it is not very understandable, and that he relies on translations.
Read more about this topic: Tages