Ovid tells of the Palladium and his visit to the site where it fell from the sky in Fast. 6.419–24.Footnote 1 My text and the pertinent part of the apparatus criticus are quoted from the 1978 Teubner of Alton, Wormell and Courtney:Footnote 2

The archaic form illi for illic in 424 is surprising in Ovid, and AWC’s note not at all convincing.Footnote 3 Following up their reference, we find that Housman’s note on Manilius reads:Footnote 4
309 illi meliores libri aut pars eorum Ouid. fast. vi 424, trist. i 1 17, ii 373, Iuu. v 42 (nisi datiuus est).
Modern commentators agree that Juvenal’s illi is dative, and modern editors print illic in Manilius and in both passages of the Tristia, leaving this passage of the Fasti entirely unparalleled. Should we then print ζω’s illic? The lectio facilior is not always wrong. Or should we take it as dative, with Bömer?Footnote 5 His firm rejection of the adverb for lack of parallels is persuasive, but it still looks to me like it ought to be a locative.
There is perhaps a third possibility. When I first began to wonder why Ovid would have written illi rather than illic here, I could not help noticing that the ‘there’ to which illi refers is, in fact, Ilium.Footnote 6 That made me suspect that Ovid wrote neither illi nor illic but the locative of Ilium: Ili, or perhaps Ilii with synizesis (Ilji). Neither form is attested, and I spent a few years wondering why the grammars consulted refused to tell me what the locative of a noun ending in -ium would be. Both forms of the genitive are found in verse and guaranteed by the metre, Ilii in Seneca (Tro. 428), Ili in Valerius Flaccus (2.473, 580), but I did not wish to presume that the locative would necessarily follow the genitive. Eventually, I noticed that there are dozens of locatives of Brundisium in Latin literature, and that both Brundisi and Brundisii are attested in prose, though Lucan can of course only use Brundĭsĭī in hexameters (2.609, 5.407). That should suffice to show that either Ili or Ilii would be correct here. Of the two forms, Ilii with synizesis would be slightly easier palaeographically, Ili slightly easier metrically, but either would be a very easy corruption. A matched pair of geographical names, Ili and Roma, would arguably provide better balance to the line. Finally, Ovid plays on the name of Troy and its founder in the preceding couplets, with Ilus repeated in 419–20 and Iliacae in 422. Would Ili or Ilji in the next couplet complete the series with an appropriate fourth term?Footnote 7 Or would it come too close after Iliacae, with the repetition adding nothing to the effect?
If the latter, there is another possibility: that Ovid wrote illi for illic, not to be pointlessly archaic, rather to continue (a bit surreptitiously) the wordplay in Ilus and Iliacae, and that we should ‘hear’ Ili as a second meaning while pronouncing (aloud or to ourselves) illi. Though I prefer my conjecture—authorial pride, no doubt—I can especially commend this reinterpretation to those with a deep-seated aversion to conjectural emendation—if any of them have read this far.Footnote 8