Ulysses is the famous hero of Homer’s Odyssey, and any poem about Ulysses must deal with the nature of his heroism. The Ulysses we meet in Tennyson’s poem is an extremely restless man. Ulysses has only been home for “three suns,” or three years, and he is “yearning in desire / To follow knowledge like a sinking star, / Beyond the utmost bound of human thought” (Lines 30-32). It’s not just that Ulysses is a hero and he’s restless; at several points in the poem his heroism is equated with his restlessness. As Ulysses says, “I am become a name / For always roaming with a hungry heart” (Lines 11-12). In other words, his name and renown and his “roaming” are entwined. Moreover, Ulysses concludes,

. . . that which we are, we are;

One equal temper of heroic hearts,

Made weak by time and fate, but strong in will

To strive, to seek, to find, and not to yield (Lines 67-70).

Here, having a “heroic” spirit is equated with the “will / To strive, to seek, to find, and not to yield” (Lines 69-70). Therefore, Ulysses equates being a hero with being restless.