"Endymion: A Poetic Romance" is a poem by English Romantic writer John Keats. The poet was one of the leading figures of the Romantic movement in England, and one of the most popular literary tropes by the Romantics was referencing Greek mythology.

The first major theme of the poem is beauty. The titular character, Endymion, was known as a handsome shepherd in the original Greek myth. Endymion was the lover of the moon goddess, Selene, in Greek mythology, who is renamed Cynthia in the poem. The first line in the poem is a reference to beauty: "A thing of beauty is a joy for ever." In the Romantic style of poetry, beauty also meant aesthetic beauty. The Romantics believed in the divine quality of beautiful design, whether they be people, objects, or natural wonders.

The other major theme of the poem is love and, particularly, trying to attain love. In the poem, Endymion literally searches for Cynthia, whom he loves. In this sense, the desire to grasp love is both literal and figurative. The poem's main narrative is essentially a journey towards love. Like all epic journeys, the path to possessing one's goal is filled with torment, long distances, and struggles. This theme is featured frequently in other Greek myths, and the poem reiterates the theme by depicting Endymion's journey to find Cynthia.

Another related theme is the nature of love itself, particularly whether love can be fleeting or it remains static. For example, during the journey to find Cynthia, Endymion falls in love with a mortal woman. When Endymion finally finds Cynthia, he tells her that he has already fallen in love with the mortal maiden, and he chooses the latter over Cynthia. When Endymion and his new love return to earth, the maiden tells him that she does not love him anymore. This shows that both Endymion and the maiden have a fleeting experience with love; they could easily fall in and out of love with different people. When it is revealed that the mortal maiden was in fact Cynthia in disguise, it is Cynthia who shows that love could be permanent, for it is Cynthia who remained loyal to her love for Endymion whilst he chose to be with someone else.