In "Ozymandias" the speaker recounts meeting a traveller "from an antique land" who tells him about an ancient ruin of a sculpture. The speaker, quoting the traveller, says that the sculpture had a "shattered visage" with a "sneer of cold command." The traveller also reveals that the sculptor captured the smug pride of the person in whose image he was making the sculpture:
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed,
In this sense, the sculptor ("the hand that mocked") and the man he was sculpting, Ozymandias the King ("the heart that fed" - on his own passions) are both immortalized and/or brought to life in this poem; as the line says, both "yet survive."
On the other hand, the poem also suggests that the work of kings and artists (including poets, a reminder by Shelley to himself an other poets) will eventually fade and erode away. In this sense, they are brought to life by the words of the traveller and given to the reader via the words of the poet. This suggests that poetry at least has the potential to outlast a sculpture. But the poem is also a warning to kings, artists, and poets to avoid being too proud because that false superiority might be recorded by artists and story tellers of history; as the sculptor did with Ozymandias. And, it is also a reminder that everything is subject to fade in time.
Romantic poets such as Shelley and Keats were very interested in the idea of the immortality of a poem, that a poem could live beyond the death of the author. If Shelley had in mind any relation to this idea when he wrote this poem, it was probably a reminder to stay humble, a lesson Ozymandias clearly never learned.