Une innovation divine

Abstract The oaths mentioned in half-dozen Hellenistic treaties of Doric cities (Messene, Rhodes, Cos, Eleutherna and Lyttos) attest to Ποτειδᾶ or Ποσειδᾶ, accusative of Doric Ποτειδάν/Ποσειδάν = Attic Ποσειδῶν. In an oath of the Megarian peddler in Aristophanes’ Acharnians (line 798), some manuscripts also exhibit Ποτειδᾶ or Ποτῑδᾶ. The accusative ending -ᾶ cannot be accounted for either as the remains of a supposed non-thematic inflection of Poseidon’s name nor as a hyper-dialectalism. Instead, Ποτειδᾶ and Ποσειδᾶ share a common origin with the so-called “apocopated” accusatives Ποσειδῶ and Ἀπέλλω / Ἀπόλλω. Dismissing the hypothesis that comparatives had shaped the accusative of the two theonyms, this paper suggests that the innovation was triggered by the co-occurrence of ἥρωα and ἥρωνα, which belonged in two secondary inflections of ἥρως, an old stem in ‑ou̯‑.