‘Your skin is illuminated with health. It is the skin of a healthy man.’

‘I am healthy. In body. Healthier than most people.’

‘Where is your problem?’

‘Before I speak I must have assurance that I can remain unidentified. That if you were to publish any findings that arise due to what you discover my name will not be found in any journals. This is of the utmost importance. Do I have that assurance?’

‘Of course. Now, you have aroused my curiosity. Tell me what is your problem.’

And so I told him. ‘I am old,’ I said simply.

‘I don’t—’

‘I am older than is meant to be.’

It took a second, but then he seemed to absorb it. His voice changed after that. Became a little less sure of itself. The question demanded to be asked, even though I could see he was scared to ask it. ‘How old?’

‘Older than is possible,’ I said.

‘Possibility is everything that has ever happened. The purpose of science is to find out where the limits of possibility end. When we have achieved that – and we shall – there will be no more magic, no more superstition, there will just be what is. Once it was impossible that this globe we are on wasn’t flat. It is not for science – and certainly not for medicine – to flatter our expectations of Nature. Quite the opposite.’ He looked at me for a long time. Then he leaned forward and whispered something. ‘Rotten fish.’

‘I’m not sure I understand.’

He sat back, pursed his lips. There was a mournful look to him. ‘No one sees the connection between rotten fish and leprosy, but it is there. If you eat too much rotten fish you will develop leprosy.’

‘Oh,’ I said. ‘I didn’t know that.’

(Of course, now, from the twenty-first century I can positively say that if you eat rotten fish you won’t get leprosy, though I have lived long enough to know that in another two hundred years it may be proven that eating rotten fish actually does cause leprosy and that Dr Hutchinson was actually right about this. If you live long enough you realise that every proven fact is later disproved and then proven again. When I was little, the average person, outside the scientific community, still believed the Earth was flat because they walked around and that is what they saw. Then people began to finally get to grips with the idea that the Earth was spherical. But then the other day I was skimming through a copy of New Scientist magazine in WH Smith’s and it was all about something called the ‘holographic principle’. It’s to do with string theory and quantum mechanics and how gravity acts like a hologram. So anyway, the mind-boggling bit is that the theory hints that the entire universe is just two-dimensional information on a cosmological horizon and that everything we think we see in three dimensions is really as much an illusion as a 3D movie, and it could all be a simulation. So really, the world (and everything) might be flat after all. And then again it might not be.)

‘So tell me,’ he said, reminding me of the question that was still in the air. A question that I knew had to be answered. ‘How old are you?’

So I told him. ‘I was born on the third of March, in the year fifteen eighty-one. I am two hundred and seventy-one years old.’

I expected him to laugh, but he didn’t. He stared at me for a long, long time as snow flurries danced busily outside the window, as if to mirror my swirling mind. His eyes widened and he pinched his lower lip between his fingers. And then he said, ‘Well. There. That settles the matter quite conclusively. Now I can set about and give you a diagnosis.’

I smiled. This was good. A diagnosis was precisely what I was after.

‘But, for proper help, you will need to go to Bethlem.’

I remembered passing the place. Hearing the dull screams from inside. ‘Bethlem Hospital? As in . . . Bedlam?’

‘The very same.’

‘But that’s a place for lunatics.’

‘It is an asylum, yes. It will give you the help you need. Now, please, I have more appointments today.’

He nodded to the door.

‘But—’

‘Please, I recommend that you visit Bethlem. It will help with your . . . delusions.’

The most fashionable philosopher at this time was the German Arthur Schopenhauer, who was still (just) alive. I had been reading a lot of him, which was probably inadvisable. Reading Schopenhauer when you felt melancholy was like taking off your clothes when you felt cold, but a line of his came back to me.

Every man takes the limits of his own field of vision for the limits of the world.

I had thought, in coming to Dr Hutchinson, I was coming to the man with the broadest field of scientific vision, the one most likely to understand my condition, and having this belief slip away felt like a kind of grief. The death of hope itself. I was beyond every field of vision. I was a kind of invisible man.

As a result, I became quite animated. I pulled a coin from my pocket.

‘Look at this. Look at this penny. It is Elizabethan. Look. Look. My daughter gave it me when I had to go away.’

‘That is an antique coin. I have a friend who has a silver coin from the reign of Henry the Eighth. A halfgroat, I think it is called. And I assure you, my friend was not born in the age of the Tudors. And that a halfgroat is rarer than a penny.’

‘I am not deluded. I promise you. I have been alive for a long time. I was there when the British found Tahiti. I knew Captain Cook. I worked for the Lord Chamberlain’s Men . . . Please, sir, you must tell me. Has someone else been to see you? A girl . . . a woman . . . talking of the same condition. Her name was Marion but she could have called herself something else. She might have been masquerading under another identity. In order to survive, we often need to—’