He had shifted the map slightly so that one edge slid from under the books. It rolled shut with a snap, so I unrolled it again and held it down with my palm.

‘Next, the ships will sail down the coast of Portugal to Lisbon,’ he said, tracing the route with the tip of his finger, ‘where, so Dom Antonio has assured us, the citizens of Portugal will rise up in his support and join our own army to seize Lisbon and evict the Spanish.’

‘Sir Francis–’ I hesitated.

‘Aye, what is it, Kit?’

‘When Drake attacked Cadiz, I remember asking why he did not attack Lisbon, and you said it was because sailing up the Tejo to Lisbon would be like walking into an ambush.’

‘Aye, quite right. But that was Drake on a raiding expedition. This time it is different, with the next King of Portugal on board.’

‘Forgive me,’ I said. ‘Perhaps I am being stupid, but will the people of Portugal know that?’

‘His standard will be flown throughout the fleet. In addition, once the raids on the northern Spanish ports have been carried out, we will ensure that news is passed secretly to the Dom’s supporters.’

Sir Francis could probably do this. I believed he could do almost anything once he set his mind to it. Privately, I thought that the attacks on the fleet would be warning enough to the Spanish that Lisbon might be our destination. Would they not take the opportunity to strengthen their defences?

‘You said there were three goals for the expedition.’ I looked down at the map, trying to think what else might be meant. Surely not a voyage round into the Mediterranean and an attack on Spain’s eastern ports?

‘The third goal, after Lisbon has been taken and the Dom crowned, is to sail south and west, to seize the Azores from the Spanish, establishing a permanent English base there, in order to hamper Spanish trade with her colonies in the New World. You can see how the three parts fit together, to weaken Spain’s world power. Destroy her Atlantic fleet. Drive her out of Portugal and thus rob her of the excellent Portuguese harbours. And finally, take control of the route to the New World. The Azores are of vital importance as a staging post for ships making the Atlantic crossing, a final stop for water and provisions.’

He rolled up the map and restored it to the shelf.

‘There is an additional goal, if the timing proves favourable. To capture the returning Spanish treasure fleet.’

Drake would be glad of that. I did not speak aloud, but I saw from the gleam in Walsingham’s eye that he was thinking the same thing.

He motioned me back to my chair and poured us both more wine.

‘Now you understand the route and purposes of the expedition, Kit.’ He sipped his wine. ‘There is indeed a mission you could undertake for me. In fact there are two.’

I held my breath. What would he say? Could I even undertake what he had in mind?

‘You can pass for Spanish, can you not?’

I nodded. ‘I grew up speaking Spanish as well as Portuguese.’

‘I thought so. I know you have worked as a translator in that language. We have an agent in Coruña, Titus Allanby. In the most recent despatch we received from him, he said he feared that his identity might have been compromised. He did not say how. He needs to leave the town, but fears to make a move as he believes he is being watched. He is privy to too many secrets for us to risk his being taken and tortured by the Spanish. In our reply, we instructed him to send no more despatches and to behave like an innocent citizen. He has good Spanish and is working as a tailor.’

‘You want me to contact him, when we reach Coruña?’

‘I want you to do more than that. I want you to bring him out. And if you cannot, you will have to kill him.’

My head shot up and I gasped.

‘Oh, do not worry. I do not think it will come to that.’ He gave a bleak smile. ‘If it looks as though the Spanish authorities will take him, he is a brave enough man to take his own life, rather than fall into the hands of their torturers.’

I gripped my hands together until I heard the joints of my fingers crack. I had volunteered for this. I would simply have to ensure that this man Titus made it back to the ships with me. I knew I could not kill a man, an ally.

‘You said there were two things you wished me to do?’

‘Aye. The other is easier. When Lisbon is taken – if it is taken – there is a man of ours in prison there. Even from prison he has been able to send us valuable intelligence.’

‘Hunter?’ I said.

‘You remember. Aye, Hunter. I want you to make sure he is found and brought safely out of prison. He can return with the expedition.’

‘If we take Lisbon.’

‘Indeed. I do not have quite the same confidence as Dom Antonio in the readiness of the Portuguese to rise up on his behalf. His birth, unfortunately, was illegitimate. There is another, legitimate, claimant to the Portuguese throne, Catherine Duchess of Braganza. At one time a man had always a better claim to a throne than a woman, even if his birth were questionable. Now our own great Queen has shown that a woman can be a mighty monarch. The Portuguese leaders, should they decide to rebel against their foreign overlords, might well prefer a woman with a more legitimate claim. The final decision could well lie with the Portuguese Cortes-Gerais, whether or not to support Dom Antonio.’

‘I knew of the Duchess of Braganza,’ I said thoughtfully, ‘but did not know she might make a claim.’ So much for Ruy Lopez’s dreams, I thought, and for my father’s life savings.

‘I do not know that she will, but it is a factor to bear in mind. Now.’ He rose briskly and took out the keys to his strongbox. ‘We must provide you with coin of the realm.’

When he had unlocked his strongbox, Walsingham gazed for a moment out of the window. He had always been careworn, but in the stronger light I saw now that his skin had the yellowish grey tinge of those consumed by some inward malady. His eyelids drooped heavily with lack of sleep and the whites of his eyes were reddened. I saw him, perhaps for the first time, as a man like other men, and not as a figure of power, the spymaster moving the pieces on the chessboard of his secret world. A sick man, anxious, vigilant, exhausted by his burden of care, worn out, body and soul, before his time. Had he been my patient, I would have said: Forget the Court and all your schemes; go home to Barn Elms and enjoy your garden this summer, for it may be your last.

Before I left with my instructions and my well-filled purse, he took me by the shoulders and studied my face as if he too were seeing me for the first time.

‘You came to us originally, Kit, because Thomas Harriot recommended you to Robert Poley for your talent with codes. And I fear that during these last years I have used you simply as a tool come conveniently to my hand. But lately I have learned more of your history and the sufferings you have endured.’

I lowered my eyes, fearing somehow that this shrewd man, fixing me with his sharp glance, might suddenly discover the truth about me.

‘You have worked well,’ he said, ‘and I hope that you find some peace or fulfilment in this journey to Portugal.’ He sighed, then added so softly I barely heard him. ‘Though I fear it is ill-conceived. When you return – if you return – I will always be glad to employ you.’

I looked up at that, and opened my mouth to speak, but he forestalled me with a smile.

‘I know, I know! Your work as a physician is of far greater importance to you. But our work is similar, yours and mine. You care for men’s bodies. I care for the body politic.’

I was astonished that he should rank me so highly and murmured some kind of incoherent thanks. I left soon after, without seeing anything of Thomas Phelippes or Arthur Gregory, the seal-forger. My purse was weighed down with Sir Francis’s heavy bag of Spanish and Portuguese coins, and tucked into the breast of my doublet was a plan of the town of Coruña. If I felt cold at the thought of what I must do there, I had no one but myself to blame.