Genitives like "axeos"

Question

I recently encountered a text written in Latin in Finland about two centuries ago using the form axeos. From context it was clear that it was a genitive, and it looks just like the Greek genitive of words like polis. But the word axis has also a Latin style genitive axis, and L&S mentions it as the only genitive.

When do genitives like axeos appear in Latin? I assume they only appear in (perceived) Greek loans where nominative and genitive would look alike, ending in -is. Is this form restricted to some contexts, eras, words, or authors? Is only used when ambiguity between nominative and genitive would be an issue? I understand the form but, frankly, I have no idea when to expect it. Any insight is welcome.

Answer 1

For what it's worth, I think this was simply a mistake.

Greek nouns ending in -is are generally third-declension i-stems, like póli-s. In Attic, these nouns tend to show an -i- in some forms and an -ei- in others, with no particular logic that I've ever learned; quantitative metathesis and contraction then make the forms even less predictable. The genitive singular of póli-s, for example, shifted from *póli-os to *poléi-os to póle-ōs.

Since these forms are so unpredictable, they have to be memorized rather than derived; I imagine Greek-speakers just learned that -is went to -eōs in the genitive, as a special rule, treating pól- as the stem and -eōs as the ending.

This writer seems to have then brought it into Latin as a sort of hypercorrection: axis is a native Latin word that never came through Greek (the Greek cognate is áxōn, with a regular genitive áxon-os), and Latin never had the vowel alternations and shifts that created póleōs.