‘Now we can use the shapes in the drawings to represent letters, remembering the dots for the last thirteen letters. Like this.’

‘Elizabeth,’ said the third man at once. ‘And again, it can be made more complex by arranging the alphabet differently, in some way decided upon in advance.’

‘Yes!’ I smiled at him, delighted that he too loved this game of hidden words. He did not smile back, but regarded me gravely.

‘Do you think you could work quickly, trying all the methods you know, watching out the night if necessary, to decipher codes in the interests of England and the Queen?’

I flushed, realising how childish I must have sounded. ‘Of course, if my poor skills would be of any use to the Queen.’

‘And to your adopted country,’ said Poley, laying his arm intimately about my shoulders, ‘which has given you sanctuary.’

I swallowed, my skin prickling at his detestable touch and his voice murmuring so close to my ear that his beard brushed my cheek. I looked steadily at Walsingham. He commanded here, not Poley or the other man.

‘Sir Francis,’ I said, ‘I would gladly be of service to you.’

I faced him with calmness now, for I found I was less afraid of this man, for all his great power, than I was of the man beside me.

Walsingham gave a brisk nod. ‘Yes. We will not always need you, only when there are too many documents and too little time for Master Phelippes to decipher himself. The work must be carried out in the strictest secrecy. To speak of it is treason.’

‘I understand.’

‘Very well. Thomas, you may take Master Alvarez and show him where you work. Test him further with some of the old letters already deciphered and see if he can work quickly enough for you.’

The small man bowed slightly to Sir Francis, then nodded me towards the door. Poley, I was relieved to see, remained behind.

It was thus that I, a Jewish girl in fear for her life, came to work for Thomas Phelippes, chief cryptographer and spymaster under Sir Francis Walsingham.

e

Until the summer when I was twelve, in 1582, my life was unremarkable and held no hint that I should one day find myself a part of Walsingham’s secret web of power.

‘I can see the house, Caterina!’ My sister Isabel was hanging out of the carriage window, her face flushed with the heat. ‘Look – there, just beyond the slope of the hill.’

I leaned over her shoulder and saw the white gleam of the walls against the jade-dark woods beyond.

My mother’s childhood home lay in the countryside not far from Coimbra, further inland along the Mondego river, on the edge of the beautiful and mysterious forest of Buçaco. It was here that my mother retired with my brother, my sister, and me, when the summer months became oppressive in the city. My father stayed on in our large stone-built town house near the university, coming out to the country from time to time. His students did not attend lectures in the heat of midsummer.

‘But diseases,’ he said, ‘know no season of rest.’

Indeed, although coughs and infections of the lungs and chest mostly passed with the winter, the summer brought its own freight of illness, often more severe – fevers and fluxes and childhood rashes. The summer I was ten there was an epidemic of measles in the city and many children died or were left blind. My mother gave thanks to God that she had been able to move us to the country before it began.

This year my sister was ten, Felipe less than two years younger than Isabel, so there was no great difference in age to divide us in our play. We ran wild as peasants, Isabel and Felipe and I, riding and swimming – my sister and I as free as our brother.

‘Let me see!’ Felipe cried now, thrusting his head under my arm and dangling so far over the edge of the window that I grabbed him by the back of his shirt and pulled him in before he turned the carriage over. I fell back into my seat and wiped the sweat from my forehead with the back of my hand.

‘Caterina,’ my mother frowned at me and shook her head at my coarse behaviour, but I closed my eyes and pretended not to notice.

The months we spent at the solar every year were a joy to me. In Coimbra things were different. My father had already detected my aptitude for intellectual pursuits and was training me to be a scholar, with the assistance of two other professors who did not despise the female mind. At that time Coimbra was one of the greatest centres in the world for humanist studies. Despite the steely grip of the Jesuits, who had been given governance of the College of Arts in the university in 1558, my father and his many novos cristãos colleagues had a remarkable degree of freedom. We knew of the Inquisition, of course. It was spoken of behind locked doors and in fearful voices, but we did not think it could touch us in enlightened Coimbra.

I loved my lessons. I learned Latin, Greek, and Hebrew, and of course French and Italian, though not English. Spanish I had spoken almost as soon as Portuguese. I excelled at mathematics and had begun the study of astronomy and philosophy. My father had initiated me into the simplest mysteries of his own profession and had inspired in me his deep and compassionate love for his fellow man. Indeed, my father truly lived to help the sick and to find new cures for diseases, spending his evenings bent over vast ancient texts of Arabic medicine. Students came from all over Portugal and Spain, even from Germany and France and Italy, to attend his lectures.

Yes, I loved my lessons, but I was a child, and sometimes a rebellious one. When the days grew soft and the warm breezes carried the salt scent of the sea up river to Coimbra, I would begin to squirm in my seat and grow inattentive.

‘Caterina,’ my father would chide me gently, ‘you have not been listening. Recite for me the febrifuge herbs, which may be used for a man of choleric temperament or in cases of feverish illness.’

So I would begin to recite the list.

‘Yarrow, vervain, peppermint, borage . . .’

‘Latin, please.’

‘Achillea millefolium, verbena officinalis, menthe piperita . . . um . . . borago officinalis . . .’

Then I would break off.

‘When shall we go to Grandpapa’s house, Father?’

‘Soon, soon. You have not completed the list. Start again.’

‘Shall you come with us?’

‘For the first two weeks. Now, Caterina, I shall grow angry with you.’

He never did. In all that we endured, I never saw my father angry.

The horses drew the carriage up the last of the steep ascent, and there were my mother’s parents, standing before the great oak door which opened on to the cool sanctuary of the house, its stone-flagged rooms shadowy behind the shuttered windows. I forgot the heat, the dust, and the fatigue of the journey and ran up the steps to hug them.

‘Come, Caterina,’ said my grandmother, ‘you are almost a young lady. You should not tumble about like a wild boy.’ But she laughed as she spoke.

My grandfather kissed me on the forehead, then held me at arms’ length.

‘You have grown two handspans at least since last summer, Caterina. You will be as tall as I before you are done.’

It was my turn to laugh, for my mother’s father was more than six feet tall and still in the full vigour of life, not much older than my father, and showing in every lineament that he was born of the ancient Christian Portuguese nobility. His ancestors had wielded great power, for the magnates in their solares or country manor houses, each at the centre of its terra, were kings every one in their own small country. But the kings of Portugal had passed laws long since that gathered these powers into royal hands, and had even destroyed the solares of some of the more recalcitrant nobles. Our family had retained its large estates, however, and the rich soil of the area provided wheat fields and olive orchards on the lower ground nearer the river, along with lush meadowland where my grandfather’s famous stud of horses grazed, together with beef cattle. Higher up, before the forest encroached, there were pockets of less fertile ground where our shepherds herded the tough little sheep. On the fringes of the forest itself the black pigs foraged on anything and everything edible.