Final answer:
Poetry concerning disappointed or unreturned love uses this theme as a means to explore deeper existential questions, evident in works like Christina Rossetti's 'Love from the North' and 'The Love Song of J. Alfred Prufrock'.
Step-by-step explanation:
The subject at hand seems to be examining poetry that illustrates disappointed or unreturned love. Renaissance love poetry often employed this theme to explore a variety of topics, such as religion, the self, the nature of relationships, and the nature of love itself. This disappointment in love can be seen in various works mentioned, such as Christina Rossetti's 'Love from the North', where the rhyme scheme and use of refrains like "I would that I were dead" intensify the mood of unfulfilled love. Similarly, 'The Love Song of J. Alfred Prufrock' deviates from the traditional upbeat notions of love songs, embedding themes of disappointment and unmet desires within its lines. Such themes are recurrent, whether in past poetic works or contemporary music, but they serve as a vessel for poets to delve into deeper existential and emotional inquiries rather than merely lament unrequited love.