A poem by the Byzantine Homeric scholar Cometas, preserved as Anthologia Graeca 15.40, may not seem quite the place to look for Indo-European poetics. It is from the ninth century A.D., its subject-matter is the Lazarus story from John 11, and what little scholarship there is on the poem does not inspire much confidence in its being a valid source for any poetics at all. (Typical descriptions of Anth. Gr. 15.40 are "metrically deficient" or "a lame Homeric cento".)
Neither date nor subject-matter, however, necessarily puts Cometas' poem beyond the Indo-European pale. Watkins, How to Kill a Dragon, p. 75, for example, sets first millennium A.D. Celtic traditions, already heavily Christianized, pretty much on a par with Vedic Sanskrit. Anth. Gr. 15.40 likewise contains its share of ancient poetic patterns. The use of rhetheon "limbs" in line 8, for example, has a possible parallel at Beowulf 2819-2820; cf. Watkins, p. 499. Line 14, referring to how Mary and Martha lamented Lazarus' fate, is also part of a broader pattern, inasmuch as it picks up a Homeric reference (Iliad 16.857 and 22.363) which occurs, in the Iliad, near the phrase lipous' androteta kai heben "leaving behind manhood and youth"; metrically anomalous in Homer, this phrase must somehow go back to the Mycenaean period.
Most striking of all is Cometas' use, twice, of kleos aphthiton "fame imperishable". At line 29 Jesus says that he intends to acquire kleos aphthiton through raising Lazarus from death, and at line 57 the multitude praises God, who has indeed acquired imperishable fame through his son. One of the best known of Indo-European poetic formulas, this phrase kleos aphthiton is possibly adumbrated in Mycenaean Greek (cf. Risch, KZ 100 [1987]: 3-11), and it finds a close parallel in Vedic sravas ... aksitam. Somehow, then, there is a very long linguistic history behind the Byzantine poem.
The "obvious" source for Cometas' usage might seem to be Homer, Iliad 9.413. Both passages in Anth. Gr. 15.40, though, deal with someone's reputation (a usage of kleos aphthiton found in Schwyzer, Dialectorum Graecarum exempla epigraphica potiora (1923): no. 316 [p. 160]) and with a physical conquest of death (cf. Hesiod, fr. 70.5); therefore, they reflect non-Homeric patterns (cf. Floyd, Glotta 58 [1980]: 133-157) more than Homeric ones.
Of course, Cometas did not know Mycenaean Greek - let alone proto-Indo-European. It is also most unlikely that he knew the archaic Greek inscription that we know as "Schwyzer 1923: no. 316". Instead, he was mining his own Greek literary tradition for patterns which we moderns can sometimes more readily observe outside of the current Greek canon and/or outside of Greek itself. The full context of the now very lacunose "Hesiod, fr. 70" was, for example, probably available to him.
In Cometas' case, then, far more than with Celtic poetry, we can see how very ancient Indo-European poetic traditions could survive to a relatively late period and into a pretty thoroughly transformed cultural and religious milieu. Recognition of the fundamental continuity of Greek poetic tradition over at least two millennia also gives one a better sense of the underlying sophistication and subtlety of Cometas' poetic oeuvre.