By 1691, the Primer was entering it's second edition and was advertised by Benjamin Harris of Boston. The oldest extant copy of the New England Primer is dated 1737.
Now I lay me down to sleep,
I pray the Lord my soul to keep;
If I should die before I wake,
I pray the Lord my soul to take."
The prayer was originally recorded in the Enchiridion Leonis which is dated 1160 A.D.