Listen! Something marvellous happened in the middle of the night when noisy folk had shut up and gone to bed. The Old English poet in The Dream of the Rood has to tell you about it. Fabulous and gleaming, then smeared with blood and sweat, the Cross on which Christ was crucified is appearing to him, one way then another, steadily but in flashes. It continues to stand steadfast, continues alternately to shine with glory or drip with gore, while telling the poet how it grew up: its innocent tree-childhood, one among many in the wood; being singled out, cut down, and carried away by the men who turned it into an instrument of torture; being put in the position of killing the young hero stretched on it dreadfully, desirously embracing him though it killed. The flashes troubled me. They reminded me of what my father suffered: obsessive images of harm occurring to his family, images of himself doing that harm. In my late teens, at university, I found ways to write about the poem that left out affect. But things on pages continued to move.

Before you enter the deep bath, roofed with a canopy of stars, you have begun to feel a change. Bodies in motion and leaping flame are reflected in polished metal, showing or casting shadows on the glitter moss of mosaic. They seem to metamorphose. Creature, you feel part of creation as process. So, at least, my friend Mike – theologian, classicist, puppeteer and trained clown – explained to ...