Unity of plot does not, as some persons think, consist in the unity of the hero. For infinitely various are the incidents in one man's life which cannot be reduced to unity; and so, there are many actions of one man out of which we cannot make an action. Hence the error, it appears, of all poets who have composed a Heracleid, a Theseid, or other poems of the kind. They imagine that as Heracles was one man, the story of Heracles must also be a unity. But Homer, as in all else he is of surpassing merit, here too—whether from art or natural genius—seems to have happily discerned the truth. In composing the Odyssey he did not include all the adventures of Odysseus—such as his wound on Parnassus, or his feigned madness at the mustering of the host—incidents between which there was no necessary or probable connexion: but he made the Odyssey, and likewise the Iliad, to centre round an action that in our sense of the word is one.
—ARISTOTLE, Poetics [c. 335 B.C.E.] I45Ia, tr. S. H. Butcher
(London: Macmillan, 1895; 4th ed. 1907), pp. 33, 35
Yet, in display of what courage and wisdom can also accomplish,
Homer has offered a useful example for us in Ulysses,
Tamer of Troy, who with shrewdness of eye made inspection of many
Cities and customs of men, who while voyaging far in his quest for
Homeward return for himself and his crew endured hardships aplenty,
Ever undrowned by the waves of adversity driving against him.
Songs of the Sirens you know of, you know of the potions of Circe:
How, had he greedily drunk them in folly, as did his companions,