"Like Beowulf, the Greek epics Iliad and Odyssey have also generated much debate about their authorship and composition.
Conventionally attributed to a single author—Homer—both works
nevertheless clearly originate in a long oral tradition and show signs
of considerable evolution in the course of their transmission history,
including the possible influence of written versions[37,38]. Since the
two Homeric epics have numerous features in common, we hypothesized that they might also have a similar pattern of sense-pauses.
However, as shown in Fig. 2a, the Odyssey has a higher proportion of
intraline sense-pauses relative to the Iliad. This difference suggests
a slight change of compositional practice between the two Greek
poems, whether due to a single poet’s stylistic evolution or natural variation across the oral tradition. "
Homer's a bit of an unusual case. The Illiad was the first written work produced after a long dark age (or close to it; I'm not sure where the consensus is right now on whether Hesiod came earlier), so Homer was drawing on a few centuries of pent-up oral tradition from a culture that had itinerant hostorian-poets. As such, he probably didn't compose all his own verses but could well have been the first to write them down. I'm not sure how effective the technique referred to in the article (stylometry) would be at teasing apart the distinction between composer-of-verse and author-of-lines.
What about Shakespeare, doesn't he have one of the most extensive authorship research? The article quickly mentions that an older analysis mistakenly attributed someone's poem to Shakespeare, to me, that only adds to the mystery of the authorship question.
