bring owls to Athens ‎(third-person singular simple present brings owls to Athens, present participle bringing owls to Athens, simple past and past participle brought owls to Athens)

 (idiomatic) To undertake a pointless venture, one that is redundant, unnecessary, superfluous, or highly uneconomical.

A calque of the Ancient Greek proverb γλαῦκ’ εἰς Ἀθήνας ‎(glaûk’ eis Athḗnas). The owl, which roosted in the rafters of the old Parthenon (the one burnt by Xerxes I), was the symbol of the city of Athens, and was sacred to its patron goddess, Athena. It was featured on Athens’ silver coins, and as Athens both mined its own silver and minted its own coins, bringing owls (either the real birds, or the coins) to Athens would be pointless.