In King Lear, the phrase “If our father would sleep till I waked him” is used in Edmund’s fake letter to Gloucester. Apparently it means “if our father were dead”. What is the origin of the phrase? Why does “sleep till I waked him” mean dead?
The phrase occurs both in the 1608 quarto The History of King Lear and the 1623 First Folio, where the play’s title is The Tragedy of King Lear. This can be seen in e.g. King Lear: A Parallel Text Edition. Second edition. Edited by René Weis. Harlow: Pearson Education, 2010.
René Weis adds the following annotation: “Edmund would not wake his father from sleep, i.e. ‘If our father were dead’.”
In the New Penguin Shakespeare, G. K. Hunter adds the following annotation: “if our father were put into my power to decide his sleeping or waking (that is, death or life).”
The association of sleep and death is not unusual in Shakespeare; it also occurs in Hamlet’s “to be or not to be” soliloquy:
To die, to sleep –
No more; and by a sleep to say we end
The heartache and the thousand natural shocks (…)
(…): to die, to sleep.
To sleep, perchance to dream. (…)
In the Oxford Shakespeare edition of Hamlet, editor G. R. Hibbard comments on the fist line: “i.e. dying is no more than sleeping.”
The association predates Shakespeare. See for example “The Parson’s Tale” in Geoffrey Chaucer’s The Canterbury Tales (quoted from The Riverside Chaucer page 292, emphasis added):
The riche folk, that embraceden and oneden al hire herte to tresor of this world, shul slepe in the slepynge of death; (…).
(“oneden” means “united”.)
The origin of the association between sleep and death in Western culture is probably biblical. See for example Daniel 12:2 (emphasis added):
And many of those who sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt.
See also the concept of soul sleep to refer to the time between physical death and resurrection.