Before the war, my family holidayed in Obersee. Every summer we trained down from Dresden, stopping at Nuremberg, then Munich, then taking the tourist train out to the lake: my father fussing about whether we would make our onward connection; my mother, who could be an absent woman, vaguely enduring my devotion – I wanted to sit nowhere except for her lap, and stroke her hair, and lay my cheek against hers. Something about my mother has always made me sentimental, and to commune with her for endless hours was usually enough to keep me occupied; this, Peter found revolting. The day after our arrival (we weren’t allowed down to the lake immediately, for a specific reason never explained to either me or my brother) we went out in the boat my father had chartered.

The lake at Obersee has an unsettling effect. The chemistry of the water traps the world’s image in uncanny perfection: the mountains duplicate, the houses flipped, and the horizon such a thin seam as to be almost imperceptible. This liquefaction of the world induced in me a kind of vertigo: horizons and skylines wobbled perilously. It was why, I was sure, my mother wouldn’t come on the boat. She said it turned her head: the glass lake, the ghost reflection, the beauty’s queasy perfection.

Obersee’s literal beauty is rather kitsch: its strident colours would appeal to a man like Ernst Steiner. It’s a sentimental place, too, since when my brother went to the Front, my family stopped going, and it always now makes me think of a place that is innocent, and unwounded, and untouched by tragedy.

As I cycled from the Bath-house, Weimar metamorphosed into another kind of Obersee. The buildings receded; rocked; and the eagles and cherubs unpeeled from the brickwork. I could still with some acuteness smell the Baths, as if the city too were chlorinated and drenched. I could no longer be sure – it was the same feeling that I had on the boat in Obersee – that if I put my foot down it would hit hard ground.

In the market the reddening apples flared.

Worrying I was about to fall off my bike, I dismounted at the Frauenplan. My vision began to prick and dot. Maybe this was what had happened to Jenö. An energetic cycle, the heat of the sauna, the forfeiture of the fast: it was enough, yes, to make a man faint. I put my hand to my pocket; Walter’s spectacles were still there. I held on to them. Soon, I would find their bigger meaning.

I heard my name called; I turned, there was my friend, Kaspar Lemke, wheeling his bicycle over. I tried to steady my vision on him. Closer to, I saw he had a coil of rope, and he was without a jacket, oblivious to the cold. ‘Are you all right?’ he said. ‘You’re white as a sheet.’

‘I might have overdone it at the pool.’