Short Answer 
The poems “Ode on a Grecian Urn” and “On Seeing the Elgin Marbles” by John Keats explore contrasting themes of art, seasonality, and time. While the first highlights the eternal nature of art, the latter addresses its evolution and the impact of time on human experience and artistic expression.
1. Identify the Authors and Themes
The two poems, “Ode on a Grecian Urn” and “On Seeing the Elgin Marbles”, are both composed by the renowned poet John Keats. The primary themes of these works focus on contrasting ideas about art: the first emphasizes the eternal and unchanging nature of art, while the latter reflects on how art evolves over time.
2. Explore the Concept of Seasonality
Both poems incorporate the concept of seasonality, highlighting the changes that accompany different times of the year. In “Ode on a Grecian Urn,” Keats notes, ‘shed Your leaves, nor ever bid the spring adieu’. Conversely, in “On Seeing the Elgin Marbles,” he describes a more fluid relationship with nature through the phrase ‘billowy main, a sun, a shadow’. This comparison underscores the dynamic aspects of nature in relation to art.
3. Analyze the Theme of Time
The theme of time is another key aspect in both poems, revealing their contrasting views. In “Ode on a Grecian Urn,” Keats captures the essence of eternal moments with the line ‘ever piping songs for ever new’, suggesting timelessness in art. Meanwhile, “On Seeing the Elgin Marbles” remarks on the inevitable decay of time with the phrase ‘rude wasting of old times’, bringing focus to the fleeting nature of human experience and artistic expression.