Wednesday, May 05, 2021
Allen Mandelbaum comes closer (he had mighty grandfathers and great-grandfathers), although he transfers the adjective away from Turnus to his ancestors. Although atavus (whence English atavism, atavistic) can mean any remote ancestor (Oxford Latin Dictionary, sense 2, citing Vergil's phrase), strictly speaking it means great-great-great-grandfather (id., sense 1), and so I would translate the phrase, in my pedantic fashion, as mighty in his grandfathers and great-great-great-grandfathers.
See the list of ancestral kinship terms in Plautus, Persa 57 (tr. Paul Nixon):
My father, grandfather, great-grandfather, great-great-grandfather, great- great-great-grandfather, and his father, too...On this line from Plautus see Alessandro Buccheri, "The metaphorical structuring of kinship in Latin," in William Michael Short, ed., Embodiment in Latin Semantics (Amsterdam: John Benjamins Publishing Company, 2016), pp. 141-175 (at 155-160).
pater, avos, proavos, abavos, atavos, tritavos...
With Vergil's combination avis atavisque compare Varro, Menippean Satires, fragment 63 Astbury = 69 Cèbe (avi et atavi nostri...).