nam maximus ultor
tergemini nece Geryonae spoliisque superbus
For our great avenger, the son of Alceus [Hercules] was at hand, exalting in the death and spoils of three-bodied Geryon…
Virgil, Aeneid VIII.201-2
It is also associated with Agrippa and Augustus, heroes of the Battle of Actium depicted on Aeneas’ shield:
parte alia ventis et dis Agrippa secundis
arduus agmen agens, cui, belli insigne superbum,
tempora navali fulgent rostrata corona.
On another part was Agrippa, with the winds and gods favourable, standing tall, leading the column of ships, on whose temples shone the beaked naval crown, the proud insignia of war.
Virgil, Aeneid VIII.682-4
ipse sedens niveo candentis limine Phoebi
dona recognoscit populorum aptatque superbis
He himself [Augustus], sitting before the snow white threshold of shining Phoebus, was accepting gifts from the people and fixing them to his proud door-posts.
Virgil, Aeneid VIII.720-2
On the other hand it is also used to describe the Trojans’ enemies, the Latins:
'Troiugenas ac tela vides inimica Latinis,
quos illi bello profugos egere superbo.
‘You see before you the Trojans and their weapons, hostile to the Latins; they have driven us here as exiles by their proud war.’
Virgil, Aeneid VIII.117-8
'en perfecta mei promissa coniugis arte
munera. ne mox aut Laurentis, nate, superbos
aut acrem dubites in proelia poscere Turnum.'
‘Behold, these promised gifts, perfected by my husband’s skill: so that no longer need you hesitate to demand battle against the proud Laurentines and fierce Turnus.’
Virgil, Aeneid VIII.612-4
And it is even associated with the monster Cacus himself, symbol of madness, chaos and evil:
caede tepebat humus, foribusque adfixa superbis
ora virum tristi pendebant pallida tabo.
The ground [of Cacus’ cave] was always warm with fresh blood, and human heads, fixed to his arrogant door-posts, would hang there, pale and wretchedly bloody.
Virgil, Aeneid VIII.195-7
In Livy (where it is used nine times in Book I, not counting proper names) it seems to have more consistently a negative flavour, as in the following examples:
Sed ipse Romulus circumibat docebatque patrum id superbia factum qui conubium finitimis negassent;
But Romulus himself was going around to all the woman, and telling them that this had been done because of the arrogance of their fathers, who had denied marriage to their neighbours.
Livy, Ab Urbe Condita I.9
Addita superbia ipsius regis miseriaeque et labores plebis in fossas cloacasque exhauriendas demersae;
He added to the list of complaints the arrogance of the king himself, and the sufferings of the people forced underground to clean the ditches and sewers.
Livy, Ab Urbe Condita I.59
But in Horace (who uses the word 13 times in his Odes) again it has a wider range of meanings, being used of a good wine (something dear to Horace’s stomach):
absumet heres Caecuba dignior
servata centum clavibus et mero
tinguet pavimentum superbo...
Your more worthy heir will consume your Caecuban wine, guarded though it is by a hundred keys, and will stain the pavement with proud, pure wine...
Horace, Odes 2.xiv.25-7
and of Horace himself, who dares to boast in the immortality of his poetry:
quaesitam meritis et mihi Delphica
lauro cinge volens, Melpomene, comam.
Accept my arrogance, earned through merit and willingly wreathe my hair with the Delphic laurel, Melpomene.
Horace, Odes 3.xxx.14-16
and with begrudging admiration the word is used in association with Cleopatra, the great enemy of Augustus and Rome (who is likened to Cacus back in Book VIII of the Aeneid):
saevis Liburnis scilicet invidens
privata deduci superbo,
non humilis mulier, triumpho.
She scorned of course his hostile fleet, robbed of all she had, and refusing to be led away in a proud triumph- no lowly woman was she.
Horace, Odes 1.xxxvii.30-2
I would suggest that this range of examples shows not only the ambiguity of the word superbus itself, but also the ambiguity of the political situation in which Virgil and Horace particularly were writing. That the same word can be used of both the heroes and enemies of Rome reflects the fact that in the recent civil war the enemies were in fact other Romans- and the supposed 'good guys' (Augustus and co, who emerged victorious and so got to propagate their version of events) were far from innocent.