The aim of this paper is to research and compare the ancient Greek poetic formulaic expression μέγα ἔπος and Sanskrit vaco mahat ~ mahad vacaḥ which can be derived from one Indo-European poetic formula. The Greek one is found in this shape only in a Theognis’ fragment (Theogn. 159–160). Nevertheless, in the Iliad and the Odyssey the formulaic expression μέγα εἰπεῖν is found. The dictionaries translate it as ‘to speak big, and so provoke divine wrath’. In this paper, Homeric passages and their relation to Theognis’ context are studied. The use of the expression in the Homeric poems and later sources gives an opportunity to assume the following semantic development: ‘to say important things’ > ‘to speak big, and so provoke divine wrath’ (‘an important utterance’ > ‘an impertinent, arrogant word’).

It is not excluded that μέγα ἔπος represents a primary form not preserved in Homeric poems due to chance and transformed in expression μέγα εἰπεῖν.

This suggestion is additionally supported by the Old Indian parallel of Greek μέγα ἔπος, namely vaco mahat ~ mahad vacaḥ. Both words containing in these phrases are cognates and this fact allows to reconstruct the protoform *wekʷos meǵh2 ‘the great word’. The contexts in the Mahabharata and the Ramayana demonstrate that this formulaic expression usually refers to the important information, often in the form of prediction or command. The Homeric context Il. 17. 333–334 is close to those of Sanskrit epics. The further semantic development in Greek tradition is to be secondary.

Despite not the full agreement in form (the counterpart of Greek μέγα is more archaic and less frequent OInd. máhi) and instability in Greek tradition (the words μέγα and ἔπος can be placed distantly in Greek), these formulaic expressions reflect common conceptions and with a high probability represent remnants of the common PIE poetic heritage.