He always arrived early at Erich’s apartment, exchanging pleasantries with a maid or governess while hoping to catch a glimpse of Delphine. More often than not, he was successful. There was a footstep in the corridor, a rustle of fabric. ‘Ah, Monsieur. I didn’t know you were coming today. I’ll fetch Erich for you.’ Then a non-committal smile and she was gone.

One afternoon, he arrived a full half-hour early and was in time to catch her playing in the music room. He stood in the doorway and watched. She nodded her head when she saw him, but carried on playing.

‘How long will you be staying in Vienna?’ he dared to ask when she had finished.

‘The arrangement is for two more months.’

Anton shifted his weight. ‘Perhaps you could come to another concert one day.’

Delphine looked out of the window, unspeaking.

‘I read an article by you,’ she said eventually. ‘In a magazine. About the diplomacy between London and Paris.’

‘Ah, yes. It was a bit dry, I’m afraid.’

‘It was interesting. I had no idea how much conversation was carried on informally.’

‘It isn’t meant to be. A government has a policy and the foreign department’s supposed to put it into practice.’

‘But if the officials on either side develop things in private, isn’t that against the rules?’

‘It’s … unusual. Because it ignores the will of the government.’

‘I hate to think what the English are plotting with the French.’

‘Yes,’ said Anton. ‘I think they’re making private treaties through the British embassy in Paris. Their Parliament knows nothing of it.’

‘It sounds dangerous. I mean … If there’s a war.’

There was a pause. Anton wondered if he had bored her.

‘Do you play the piano?’ said Delphine.

‘No. I had lessons when I was at the Gymnasium. It was compulsory up to a certain age. But I was never any good. And I was allowed to give up after two years.’

‘Come and sit here.’ She pulled a chair up beside the piano stool. ‘Show me.’

Anton, after a moment’s hesitation, sat down and played a schoolboy exercise, the first that he and Friedrich had been taught.

‘Can you do this?’ She played a variation.

‘Probably.’

‘It’s the same as what you’ve just played, but you use these black notes as well. It sounds better.’

‘Yes.’

‘Keep doing that.’

While he did as he was told, Delphine began to play a melody in a higher register. Anton concentrated on his repetition, trying not to look at Delphine. She struck a chord between his two hands before returning to her end of the keyboard. Eventually, Anton relaxed enough to listen to the sound they were making, her descant on his schoolboy repetition. He began to smile.

Delphine began to laugh. ‘The look on your face!’

‘It’s just that it seems … like magic to me. I’m so bad at it.’

‘Never mind. You like Mahler and you hate Strauss. That’s a start.’

‘Where shall we go next, then? You must choose a concert. Look at the newspaper and tell me the one you would most like to go to. I’ll buy the tickets.’