The Einstein-Rosen bridge could have brought us to that answer, had it been possible to travel back in time, at least, by now when technology is shaking up the world as in just about everything else. Alas, we have to proceed without that knowledge and carry-on investigating using evidences we have available to us. There is, as such, no recorded time that notes the first ever verse.
When the Sumerian civilisation, the oldest civilisation known to us, reveal in its remains, verse texts, Kesh Temple Hymn and the Instructions of Shuruppak, dated 2500 BCE, we can still be certain that the story of verse began far earlier than then, because for the script of any language to evolve and develop, we know, takes centuries.
Furthermore, we can also ascertain this that before the advent of script and writing, verse was prevalent. How? Orally, and even before verse was articulated, it had to take birth in the minds of its authors. German philosopher and a tall figure of the German Idealism, Georg Wilhelm Friedrich Hegel, in Aesthetics: Lectures on Fine Art explores art, and according to him art evolves into forms based on the “concept of beauty.”
Shedding light on a threefold mode of perception, Hegel, divides art into, first, "the visual arts, which work out their content for our sight into an objective external shape and colour," such as that of architecture, sculpture and painting. Second, "the art of sound, i.e., music" and finally, "poetry which as the art of speech, uses sound purely as a sign in order by its means to address our inner being, namely the contemplation, feelings, and ideas belonging to our spiritual life."
Therefore, moving from material realisation of beauty, art achieves spiritual realisation in poetry — art ascends to “inwardness”, verse being its ultimate form.
One of the ancient languages, Sanskrit, in written form, is, in fact, an undesired occurrence; a later development of the language, which was composed and codified to only be transmitted orally. The written practice is thought to have begun sometime in the second millennium BCE. In fact, Pānini the Sanskrit philologist and grammarian of the fourth century BCE — in his treatise on Sanskrit phonetics, Pāninīya Shiksha, also orally composed — mocks the people who wrote down Ancient texts, calling them Likhita Pathaka to mean a literate person, which, today, essentially, is to frown upon those who could write and read, like one might take a jibe at an illiterate person.
गीती शीघ्री मशरःकम्पी तथा मिखितपाठकः ।
अनथकज्ञोऽल्पकण्ठश्च षडेते पाठकाधमाः ॥ ३२॥
"The ones who recite hurriedly from a written text, nodding their heads will not know the true meaning of the text, and are bad at reciting."
———Panini's remark in Sanskrit with English translationIt is important to note that the lexical semantics of words in early Sanskrit texts is a pleasing derivative of sound groups. Before conclusions are drawn, let us be cognisant of the fact that there’s more to the syntax of Sanskrit; the Ancients, having prioritised sound over meaning, formulated the syntactic arrangement of words in Sanskrit verses based on vibrations. So, then the pertinent question arises, are the Sanskrit verses composed devoid of meaning? Not entirely; it is a matter of literal meaning as opposed to implied or suggested meaning. This is also why, the Ancients’ overarching objective to put emphasis on sounds in words and verses in Sanskrit over its meanings is a subject of considerable interest to many Indologists.
Similarly, does our muse letter, 'O' have a meaning? Only when it is uttered can we decipher whether it is an 'O' of joy or surprise or sadness or dismay or pain or so on and so forth. Besides, we need not share a common language for the expression O’s meaning to be worked out. It, somehow, is universal and so is verse.