Sleep and Despair—they're both written with capital letters in "Come Sleep! O Sleep," which tells us that the speaker thinks of them as characters or supernatural beings. Yeah sure lots of poets have done this, and it's totally a conventional thing to do, but it does have its purpose. The presence of two supernatural beings that seem like enemies (Sleep can stop Despair's dart-throwing, for example) makes the speaker seem like a pretty important guy; inhuman, cosmic forces are playing games with his life and destiny.
Questions About The Supernatural
What is the effect of making Sleep into an actual, personified being?
What is the effect of the speaker in essence bargaining with Sleep? Why isn't the speaker the one in charge of his own body?
Why doesn't the speaker mention dreaming at all in this poem?
Chew on This
Sometimes we attribute things like sadness and sleep to supernatural beings, because we can't explain them by any other means. It's like a kind of cosmic shrug.
The presence of the supernatural in this poem gives it an air of mystery and intrigue, making the speaker's travails just a tad bit more interesting—just a tad.