Final answer:
The theme of "Ozymandias" is the transient nature of power and the vanity of human grandiosity, which is reflected in the ruined statue that once boasted great power but now lies forgotten.
Step-by-step explanation:
The theme of "Ozymandias" by Percy Bysshe Shelley can be summarized as the ultimate vanity of human grandiosity and the transient nature of earthly power. The poem describes the ruins of a once-great statue of a ruler, Ozymandias, whose inscription boasts of his unmatched power. However, the ruins lie in an empty desert, signifying that despite his claims, his glory was not enduring. This reflects the wider vanitas theme, which is a moralistic message about the ephemerality of life and the futility of pride and arrogance. Examples of the vanitas theme are also apparent in still life paintings from the same period, which included symbols such as skulls or wilted flowers to represent the transience of life.