During the summer, I had a conversation with the former Archbishop of Canterbury, Rowan Williams, about Bach. Simon Russell Beale was playing Bach in a play at the Bridge Theatre and I knew that Dr Williams had written poetry about Bach’s view of the universe. His explanation of the notion of mathematical harmony, and therefore the vibration of the heavenly spheres, was especially moving.

A little while later, Dr Williams got in contact with me again. He told me, in as understated way as possible, that he knew an artist who had designed a Cross of the Cosmos, containing moon dust, and that the Cross would be consecrated by Bishop Williams at Westminster Abbey in November. Might I be interested in taking up the story?