The poem's opening lines vividly introduce the speaker—Ulysses, the king of Ithaca—and establish that he isn't too happy with his situation. These lines also make it clear that the poem is a dramatic monologue, a speech uttered by a particular character in a particular context, similar to a monologue delivered by a character in a play. Ulysses's name isn't actually mentioned in the poem. Instead, the poem's title indicates who the poem is about: Ulysses, the protagonist (with his Greek name of Odysseus) of Homer's ancient Greek epic The Odyssey. The Odyssey is one of the most well known works of world literature, and so Tennyson would have expected his readers to be familiar with Ulysses/Odysseus and his story.
In Homer's tale, Odysseus spends 10 years fighting in the Trojan War and 10 years in adventures at sea struggling to return to his island home of Ithaca, and to his wife, Penelope, and his son, Telemachus. Odysseus's driving motivation throughout The Odyssey is to get home, so readers might be surprised by the opening lines of Tennyson's poem—which describe how unhappy Ulysses is with life on Ithaca. Ithaca is not a beloved homeland, it is merely "barren crags"; Penelope is not the woman he fought for years to return to, she is simply "an aged wife." The strong contrast Tennyson draws between the reader's prior idea of Ulysses and this new image presented in the poem is one of his strategies for engaging the reader's curiosity and interest: if Ulysses spent years traveling the world attempting to reach home, why has his home left him so unhappy?
The opening lines start to present an answer to that question. Ulysses seems to be unhappy with the idea of growing old. He does not directly call himself old—almost as if he cannot stand to admit it—but he calls his wife "aged," and if he is "Match'd" with her, then he must be aged as well. He also complains that he is "idle" and that he is stuck by a "still" hearth. He is frustrated because he does not feel he is doing satisfying work and because he is trapped in one place.
This dissatisfaction comes partly because Ulysses feels little connection to the people he rules. He describes them in terms that are often applied to animals or beasts. They are "savages" who do nothing but sleep and eat and "hoard" goods, like animals storing up food for hibernation. Worst of all, they "know not" Ulysses. That is, they do not understand the kind of man he is. He has traveled the world, while they have only ever seen the "barren crags" of Ithaca. He is also dissatisfied because, while his people are content to live and die on this island, Ulysses cannot stand being "still."
The diction of the opening lines creates an audible sense of Ulysses's frustration. There are many harsh and cacophonous consonants that could be voiced almost as one were spitting them out—the /t/ sound in "little profits," "Match'd," "mete," and "not," the /p/ in "profits" and "sleep," the /k/ in "king," and, to a certain extent," the /d/ sound at the end of "hoard" and "feed."
These opening lines suggest that, deep down, Ulysses does not feel his true identity consists in being king of Ithaca. Ulysses does not say "sit idly by this still hearth"; he says "an idle king, / By this still hearth," almost as if the king were a person other than himself. He distances himself from the role. But when he speaks of how little his people understand him, he uses an emphatic first-person pronoun: "and know not me." His true identity lies in this side of him that his people (and perhaps even his wife) do not see or understand—the part of him that cannot stand being "still."
The poem's meter serves to emphasize Ulysses' strong emotions. The poem is written in unrhymed iambic pentameter (blank verse). This is the meter used by probably the most famous epic poem in English, John Milton's Paradise Lost, so it is a fitting meter for a poem about the hero of one of the greatest epic poems in Greek. There are frequent irregularities in the meter, however, that serve to enhance the meaning of particular lines. For instance, line 2 could be scanned:
By this still hearth, among these barren crags,
There is an irregular stress on "still," creating a spondee. The spondee slows readers down, forcing them to linger longer on the phrase "by this still hearth," almost reproducing the feeling of being still. There is another spondee at the end of line 5:
That hoard, and sleep, and feed, and know not me.
The wholly regular meter in the first three feet creates an impression of a regular, repetitive pattern, just as the people of Ithaca fall into a repetitive pattern of doing nothing but hoarding and sleeping and eating. The spondee, coming at the end of the first sentence in the poem, breaks the pattern, just as Ulysses wishes to break the pattern of daily life on Ithaca. It also gives strong emphasis to the idea that Ulysses feels misunderstood by his people, as if he cannot be his true self among them. Ending the line and the sentence on the word "me" indicates that an important theme of the poem will be Ulysses's exploration of his true nature and his true identity.