Vergil wrote (Eclogues IX.51–4), quoted by Draconis in this answer:
Omnia fert aetas, animum quoque. Saepe ego longos
cantando puerum memini me condere soles.
Nunc oblita mihi tot carmina: vox quoque Moerin
iam fugit ipsa.
This passage is spoken by Moeris (in the first person and the third person!). The first two lines mean:
Age takes all, even memory. I recall myself as a boy, often putting away the long Suns [i.e. concluding the long summer days] by singing.
Now, how do we make sense of oblita carmina? I'll post my current thinking in this question; I'm looking for confirmation or correction.
1. The carmina forgot?
Obliviscor is a deponent verb, so oblita is active. Literally, the line would seem to mean:
Now so many songs have, to me, forgotten.
with an omitted sunt. Did the songs forget the summer days? This seems to push figurative speech awfully far.
Hey, maybe it's oblĭta, past participle of oblinere, to daub over, as with mud. This is not a deponent verb, so we have:
Now so many songs have, to me, been blotted out (as if) by mud.
That at least works grammatically, but does it scan? No. Both ob-lĭ-tă and ŏ-blĭ-tă would yield three short syllables in a row:
Nunc ob/līta mi/hī tot/carmina: / vox quoque / Moerin
3. Deponent with passive meaning?
Could Vergil have invoked poetic license, asking the listener to accept a passive meaning for oblīta?
Now so many songs are forgotten to me.
Does Vergil really take such liberties with grammar, though?
4. The aetas forgot?
Oblīta could agree with aetas, so the sentence has an omitted est:
Now the age has forgotten so many songs for me.
Isn't the subtext of this entire poem that Octavian's confiscation of land for the army has despoiled the land, tradition, and art—that "the din of arms has silenced poetry"? Or at least Vergil's poetry, if his farm was among those confiscated?
Aetas also means a period in history. So Omnia fert aetas, animum quoque has a double meaning: "The present age carries all, even the soul"—the present age referring to the rule of Octavian. Isn't this the kind of subtle political subversiveness that Vergil is famous for?
Just before this passage, there is a quotation from one of Moeris's forgotten songs, celebrating the rise of Caesar's star, which would make "the fields rejoice with crops". The message seems to be: in the present age, of Octavian's confiscation of farms, those songs of Caesar's beneficent leadership are obsolete and forgotten.