Sus cum Minerva certamen suscepit

Erasmus Adagia 41:

Sus cum Minerva certamen suscepit
A pig undertakes a contest with Minerva

The same or at least as close as possible to this is found in Theocritus’ Idylls.

Ὗς ποτ᾽ Ἀθηναίαν ἔριν ἤρισε
A pig once challenged Athena to a quarrel

It is said whenever the ignorant and dull-witted, ready to fight, are not afraid to challenge men of the highest learning in a literary competition. Theocritus commentator writes that the phrase is commonly used thus: Ὗς ὢν πρὸς Ἀθήνην ἐρίζεις (though a pig, you quarrel with Athena). Some scholiast adds that ἐρίζειν is used for those who compete with words and ἐρείδειν for those who compete with deeds – which makes it all the more laughable, if an unteachable pig competes with Minerva, the guardian of studies.

Cum hoc aut idem aut certe quam maxime finitimum, quod apud Theocritum
legitur in Hodoeporis:

Ὗς ποτ᾽ Ἀθηναίαν ἔριν ἤρισε, id est
Cum diua est ausus sus decertare Minerua.

Quoties indocti stolidique et depugnare parati non verentur summos in omni
doctrina viros in certamen literarium prouocare. Theocriti enarrator sic efferri
vulgo παροιμίαν scribit: Ὗς ὢν πρὸς Ἀθήνην ἐρίζεις, id est Sus cum sis, cum
Minerua contendis. Scholiastes nescio quis addit eos ἐρίζειν dici, qui verbis
certant, ἐρείδειν, qui factis, quo magis ridiculum est, si sus indocilis certet cum
Minerua disciplinarum praeside.

The reference to Theocritus is to Idyll 5, line 23:

Comatas
By these Nymphs of the lake—and may they be kind and propitious to me—I, Comatas, did not steal away with your pipe.

Lacon
May I have the sufferings of Daphnis if I believe you.6 But if you would like to wager a kid—not a big stake, after all7—then I’ll compete with you in song until you give in.

Comatas
A pig once challenged Athena.8 There: the kid is my stake; now you put forward a fat lamb.

Lacon
And how will that be fair, you trickster? Who shears hair instead of wool? Who wants to milk a wretched dog when a goat is at hand which has just given birth for the first time?

Kοματας
οὐ μάν, οὐ ταύτας τὰς λιμνάδας, ὠγαθέ, Νύμφας,αἵτε μοι ἵλαοί τε καὶ εὐμενέες τελέθοιεν,οὔ τευ τὰν σύριγγα λαθὼν ἔκλεψε Κομάτας.

Lακων
αἴ τοι πιστεύσαιμι, τὰ Δάφνιδος ἄλγε’ ἀροίμαν.ἀλλ’ ὦν αἴ κα λῇς ἔριφον θέμεν, ἔστι μὲν οὐδένἱερόν, ἀλλά γέ τοι διαείσομαι ἔστε κ’ ἀπείπῃς.

Kοματας
ὗς ποτ’ Ἀθαναίαν ἔριν ἤρισεν. ἠνίδε κεῖταιὥριφος· ἀλλ’ ἄγε καὶ τύ τιν’ εὔβοτον ἀμνὸν ἔρειδε.

Lακων
καὶ πῶς, ὦ κίναδος τύ, τάδ’ ἔσσεται ἐξ ἴσω ἄμμιν;τίς τρίχας ἀντ’ ἐρίων ἐποκίξατο; τίς δὲ παρεύσαςαἰγὸς πρατοτόκοιο κακὰν κύνα δήλετ’ ἀμέλγειν;