Along with Wordsworth, Lord Byron, Shelley and Keats, Alfred, Lord Tennyson is considered one of the premiere English Romantic poets. Romantic poetry often focused on nature. For example, one of Wordsworth's most famous poems, "I Wandered Lonely as a Cloud" is simply the poet's recollection of what it was like to come upon a field of daffodils and the beauty they provided him.
Likewise, Tennyson focuses on an eagle, perched high on a mountain cliff, as the subject of this short, two stanza poem. He uses both personification and simile to describe the eagle as the bird watches from high above, and then dives to the sea below for his prey. The eagle is personified in the first stanza: "He clasps the crag with crooked hands". In the second stanza, Tennyson uses a simile to express the eagle's hunt:
He watches from his mountain walls,
And like a thunderbolt he falls.
In nature, the eagle is a king, very high on the food chain. The poem reflects this predominance. Nothing can touch the eagle on its lofty precipice. It has a complete view of the world below and hunts ruthlessly. The eagle is compared to a thunderbolt, and the extreme power that natural element brings to the world. Tennyson also describes the sky as "azure," defining its deep blue quality, and the sea as "wrinkled," taking into account the motion of the waves.