Of all the strange circumstances that surround the composition of The Rime of the Ancient Mariner, one above all is worth keeping in mind. It was finished in 1798, six months before Coleridge ever went to sea in a ship, ‘and then only to sail from Yarmouth to Cuxhaven’.

This point was stressed by John Livingston Lowes, the early 20th-century Harvard scholar, in his analytical masterpiece The Road to Xanadu (1927). His point was stark. The poem, loaded with Coleridge’s lurid visions – in Charles Burney’s frank estimation, ‘a rhapsody of unintelligible wildness and incoherence’ – did