“Perhaps the strangest aspect of this prophetic poem is that it is haunted by a double. There are two versions of ‘The Rime of the Ancient Mariner’. The first begins the 1798 Lyrical Ballads by Wordsworth and Coleridge, and the second is the 1817 revision published in Sibylline Leaves, to which Coleridge added a running marginal gloss explaining away, in a pastiche of 17th-century prose, his zombified sailors and ‘slimey things with legs’. Between the first version and the second, Coleridge reconsidered his faith: in 1798 he was a Unitarian who had cut himself off from the Church because he disapproved of redemption, and by 1817 he had softened into an Anglican.

“’The Ancient Mariner’ is a casualty of this change of faith.”

-Frances Wilson, Shipwrecked: looking for God in The Ancient Mariner- Malcolm Guite’s religious portrait of Samuel Taylor Coleridge – 2/13/17 – New Statesman