In line 19 of "The Second Coming," the "stony sleep" is that of

The “stony sleep” refers to the ancient sphinx-like supernatural image that appears in the poem. Its sleep lasts for “twenty centuries” and is disturbed by the “rocking cradle,” an allusion to Christ’s birth. So the sleep is that of an evil supernatural being, not of God, early Christians, or people living at the time of the poem.

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