A few days later, Martha stopped her in the hall. ‘Lena, please would you make sure the bedroom at the top of Lamp Court is made up? My sister’s arriving this evening from London.’

‘Your twin sister, Fräulein?’

‘I have only one.’

‘I can’t wait to meet her.’

‘Well. You must promise not to like her more than me.’

‘I promise.’

‘It’s time we had another cup of tea, isn’t it? Maybe tomorrow afternoon?’

‘I’ll come when I’ve finished sweeping up the leaves with Joseph.’

The teatime meetings happened roughly once a month and Lena no longer feared them. While Martha never confided personal feelings, she let Lena see that she was anxious about aspects of the Schloss.

‘We need to find some new doctors,’ she said, pouring tea from a brown pot. ‘Dr Bernthaler’s seventy next year.’

‘That’s the same as Mary,’ said Lena.

‘Yes. Franz used to do a lot of work with my father when he first came. It was before I was born, can you believe? As a young man, he’d studied in Frankfurt with two men called Nissl and Alzheimer. He was always a researcher at heart, I think. He taught my father quite a lot. They used to spend all evening in the cellars looking at bits of brain tissue under a microscope.’

Lena found the idea of taking bits of brain from dead people repulsive.

‘Why don’t you take over, Fräulein?’

‘I’m not a doctor.’

‘But you’re a … You know.’

‘Therapist? Well … Before all that, I taught for a time at a school in London. Young children. I enjoyed it, but I felt the pull of … I don’t know, I felt anyone could teach children their tables and spelling. Also, I wanted to come back here, where I had roots.’

‘Was there a young man?’ said Lena.

Martha laughed. ‘Young men did come by occasionally. We lived in some rooms in Chelsea, a part of London near the river. I think Charlotte was always more interested than I was. I don’t know. It was a bit … unconventional, the life we lived. People in London called it “bohemian”, though of course that means something rather different in this part of the world.’

‘I’ve always liked the sound of it,’ said Lena. ‘Bohemia. I bet you had a lot of suitors, you and your sister.’

What she wanted to ask was whether they had slept with men, as she had, and if she had enjoyed it, that feeling of a man inside herself. She thought Martha would be attractive with her fair skin and her smart clothes, but perhaps men might not like her glasses or might think her manner too brisk.

‘I was never sure about the idea of one man,’ said Martha. ‘When I was a child all the books I read seemed to suggest there was a prince for every girl. Then, when I grew up, the textbooks and the lectures seemed to talk about life in a very different way. About sex appetites and women being naturally in need of more than one man. There was a book by someone called Otto Weininger which said all women were designed to sleep with as many men as possible. It was very popular in its day.’