Shelley was a Romantic poet, and as such, was very interested in the sublime power of nature and both individual’s and art's connections to it. This poem addresses those concerns on a grand scale. Shelley was also a political writer. Several years after the publication of “Ozymandias,” he published a pamphlet entitled "A Philosophical View of Reform" in which he called for an end to tyranny and discussed the history of empires crumbling over time. “Ozymandias” displays many of Shelley's concerns, both in terms of its depiction of man versus nature and its apparent politics.

“Ozymandias” has several literary predecessors and contemporaries. Shelley and his friend and fellow writer Horace Smith challenged each other to write about Ozymandias and his destroyed statue after reading about the statue in a description written by the ancient Greek writer Diodorus Siculus. Siculus described the pedestal of the real-life statue as containing an inscription that read "King of Kings am I, Osymandias. If anyone would know how great I am and where I lie, let him surpass one of my works." Shelley's poem then, is a re-telling of an already-told story, and one can argue that in retelling the story in his poem Shelley is actually taking up Osymandias's challenge—that in writing "Ozymandias" Shelley sought to surpass Osymandias's works.

The historical Ozymandias’ legacy was not actually entirely dead when Shelley wrote this poem. In fact, Shelley may have been inspired to write this poem by newspaper reports that the British Museum had acquired the large head of an Egyptian statue: a statue that later turned out to be of Ramses II, also known by his Greek name, Ozymandias. This fragment of a sculpture of Ozymandias produced not despair at the futility of human achievements, but rather excitement, enthusiasm, and ultimately, preservation in a museum, where the artifact would be protected from the elements and, as much as possible, from time itself.

Some critics believe that the poem is partly—though certainly not entirely—a response to the rise and fall of the Emperor Napoleon, in France. In this reading, the poem serves as a warning to those who seek political and military power, that they will fall be eventually be forgotten, just as Ozymandias was.