When were /k/ and /q/ first distinguished in the Greek or Latin alphabet?

Question

Nowadays, in languages which make a distinction between velar and uvular stops, it's common to use K for the first and Q for the second. This is best-known nowadays from transcriptions of Arabic names, such as Qatar and Kuwait.

Neither Latin nor Greek had a velar-uvular distinction, but they both inherited suitable letters for it (from Phoenician, which did have that contrast). At some point, people evidently started using these letters for their "original" (Phoenician) purpose again.

When did this "original" use start back up again? In other words, when was the first time that the Latin letter Q or the Greek letter Ϙ was used to distinguish a uvular sound from a velar one?

Answer 1

There are not many Latin-text sources for Phoenician-proper, only for its descendant/close relative Punic, the language of Carthage which was settled by Phoenician colonists from Tyre

Luckily there is a reasonable body of Latin-text Punic including several inscriptions from Tunisia and Libya, as well as some lines of dialogue in Plautus' play Poenulus ("the little Phoenician"). There is a trend for these texts to represent kap as <ch> and qop as <c> although kap is also frequently written <c>. This is not believed to represent frication of the kap as in Hebrew begedkefet, but rather aspiration, as Greek texts fairly consistently use chi to transcribe Phoenician kap, and kappa to transcribe Phoenician qop even in quite early transcriptions long before chi had itself become a fricative

It's worth saying though, that most of these classical sources were not interested in precise transliteration in the way a modern linguist would be and, as orthography generally had not been standardised, these transcriptions were pretty ad hoc