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.