What is the main theme of Sonnet 18 by William Shakespeare?
The main theme is that the object of the speaker’s affection (his beloved) will live forever in the poem he’s written about her. The idea is that, even though the beloved will eventually die, her beauty and goodness will live on and be remembered whenever people read Sonnet 18. Death won’t be able to brag about taking the beloved because she will achieve a kind of immortality through art.