The night is come; like to the day. Sir T. Browne. [Evening.] First published in the 1642 edition of his Religio Medici, Pt. ii., § 12, and is thus introduced in speaking of sleep:—
"It [sleep] is that death which we may be literally said to die daily; a death which Adam died before his mortality; a death whereby we live a middle and moderating point between life and death. In fine so like death I dare not trust it without my prayers and an half adieu unto the world, and take my farewell in a colloquy with God:—
“The night is come; like to the day," &c. [extending to 30 lines]. "This is the dormitive I take to bedward; I need no other laudanum than this to make me sleep; after which I close mine eyes in security, content to take my leave of the sun, and sleep unto the resurrection."
From the above-named 30 lines, the cento in common use has been compiled. It is also sometimes given in an altered form as "The sun is gone: like to the day," as in Baptist Psalms & Hymns, 1858. Original text in The Camelot Classics, London, W. Scott, 1886.
-- John Julian, Dictionary of Hymnology (1907)