Laudator Temporis Acti

Guillermo Galán Vioque, in his commentary on Martial 7.42.6 (Alcinoo nullum poma dedisse putas), explains:

a set phrase to express the idea of 'giving someone something he does not need', similar to the English 'carrying coals to Newcastle'; cf. the Spanish 'dar trigo a Castilla' and the German 'Eulen nach Athen tragen'. Cf. Ov. Pont. 4.2.9-10: quis mel Aristaeo...poma det Alcinoo (OLD s.v. 1b). Cf. A. Otto, Sprichwörter, R. Häussler, Nachträge zu A. Otto, R. Tosi, Dizionario, 220 § 474. Cf. also Hor. Sat. 1.10.34: in silvam non ligna feras insanius, Ov. Am. 2.10.13-14: quid folia arboribus, quid pleno sidera caelo, / in freta collectas alta quid addis aquas? Mart. 11.42.4: thyma Cecropiae Corsica ponis api! Alcinous was the mythical king of the Phaeacians and owner of an orchard where all sorts of fruits grew in great abundance; cf. Od. 7.112-131.

Here are translations of the foreign passages and phrases quoted by Galán Vioque:

• Martial 7.42.6: Do you think no one ever gave fruits to Alcinous?
  
• Spanish: To give wheat to Castille.
  
• German: To carry owls to Athens.
  
• Ovid, Epistulae ex Ponto 4.2.9-10: Who would give honey to Aristaeus [the inventor of beekeeping] or fruits to Alcinous?
  
• Horace, Satires 1.10.34: You couldn't do anything crazier if you carried wood into a forest.
  
• Ovid, Amores 2.10.13-14: Why do you add leaves to trees, stars to a full sky, a cup of water to the deep sea?
  
• Martial 11.42.4: You're putting thyme from Corsica in front of a bee from Athens!
  

None of the secondary works cited by Galán Vioque are available to me. What puzzles me is his implication that we should look to German for the source of "owls to Athens". It's a Greek proverb, γλαῦκ᾽ εἰς ᾽Αθήνας, known as early as Aristophanes, Birds 301: τί φῄς; τίς γλαῦκ' Ἀθήναζ' ἤγαγεν; (What are you saying? Who brought an owl to Athens?). See also Cicero, Letters to His Friends 6.3 and 9.3, Letters to His Brother Quintus 2.15.4. The point of the proverb is that the owl was the bird sacred to Athena, patron goddess of Athens; Athenian coins were stamped with the figure of an owl; and because Athens mined its own silver and minted its own coins, there was no need to import "owls" to Athens. To express the same thought, the ancient Greeks also said ἰχθῦς εἰς Ἑλλήσποντον (fish to Hellespont), according to Arthur Palmer on Horace, Satires 1.10.34.

A Festschrift in honor of famed Greek scholar K.J. Dover was entitled Owls to Athens (Oxford: Clarendon Press, 1990). In other words, Dover is so expert in ancient Greek that offering him the scholarship of others is like carrying coals to Newcastle.