I think that one of the most essential points of Tennyson's poem can actually arise from a particularly poignant moment in Homer's Odyssey. In Book XI, Odysseus speaks with Achilles in his journey of the Underworld. Odysseus tells him how impressed he is with his hold over the Greeks even through death and Achilles is able to articulate a pearl of wisdom that Homer develops as only understood through experience:
O shining Odysseus, never try to console me for dying.
I would rather follow the plow as thrall to another
man, one with no land allotted him and not much to live on, than be a king over all the perished dead.
For Achilles, there is nothing that can take the place of life, and the process of living. Immortality is not worth the price of failing to live life.
In the most connective of ways, Tennyson develops his vision of Ulysses in the poem in much the same way. For Tennyson, Ulysses' return home to Ithaca is only temporary. Tennyson's poem details how like Achilles, Ulysses comes to value life. He cannot endure the mundane task of staying in a domestic capacity and simply ruling. The exploits of battle, the joy of life in pursuit of a goal that underscores life is where his heart lies. Like Achilles, he cannot perceive life as worth living as being "king over all the perished dead." In the poem's sense, this "perished dead" is the life in which there is not a sense of adventure and excitement. In recognizing this, the poem is a statement as to why Ulysses must leave again and commit himself to a life in which he sets out "to strive, to seek, to find, and not to yield." This sentiment becomes the basic element of the poem.