I came across this: Ζηνὸς ἐριβρεμέτεω
ἐριβρεμέτεω is masc genitive from ἐριβρεμέτης. So, why isn’t it ἐριβρεμέτεος? I have the feeling I’m missing something obvious here, but can’t figure out what.
Compare:
Iliad 1:1: μῆνιν ἄειδε θεὰ Πηληϊάδεω Ἀχιλῆος…
This is the Ionic genitive of masculine 1st declension nouns ending in -ης (not the 3rd declension), equivalent to -ου in Attic.
The original form was -αο (long alpha) but this changed to -ηο in Ionic when α (long alpha) changed to η in Ionic, and then, by a process known as “quantitative metathesis”, the long vowel η became the short vowel ε and the short vowel ο became the long vowel ω.
The combination was pronounced as diphthong, i.e., a single syllable. This happened wherever metrically possible in the inherited formulas of the Homeric language, as the first line of the Iliad quoted by Markos illustrates, but in some positions it wasn’t metrically possible, for example in the last foot of a hexameter, so the ending -αο was generally maintained in that slot.
The Attic equivalent was simply borrowed from the second declension.
Ah, of course. Thanks. That’s what happens when you don’t read Greek for 6 months.