so that your message, “The king is in London,” now reads “maxdbgzblbgehgwhg.” The important thing is that, after a given number of letters, normally twenty-five, you move to the next word, in this case Mordecai, and start again, so that m=a, n=b and so on. Variations on this method exist, of course. But the point is to ensure that the value of letters changes sufficiently frequently for it to be all but impossible to make the code out unless you have the text on which it is based. I will explain why this was important later on.

I was worried that the scripts given me might be of this type; I could possibly have deciphered them eventually, but not in the time allowed. If I am vain about my abilities, it is with some justice; only one text has ever defeated me, and that was in special—though important—circumstances which I will deal with later. But every time I am handed a coded letter, I know that bitter experience of failure might be mine once more, for I am not infallible and the possible variant combinations are virtually infinite. I myself have constructed codes which are unreadable without the right texts for decipherment, so it was perfectly possible that others could do so as well; indeed I am surprised that I have not been defeated more often, as it is easier to construct an impregnable code than it is to breach its walls. Fortunately, in the case of Mr. Bonnet’s letters I was again lucky—the authors were as simple-minded in their approach as were the Royalist conspirators in their day. Few people, I find, are prepared to learn from experience. Each epistle had a different code, but they were simple ones and each was long enough to allow me to fix the meanings. At seven the next morning, accordingly, I presented myself once more to Mr. Bennet, and handed over my labors.

He took them, and glanced over the fair copy I had prepared. “Would you summarize them for me, doctor?”

“They appear to be a group of letters to one individual, probably in London,” I said. “All specifying a date, January twelfth. There are references in two of them to weapons, but not in the others. One mentions the kingdom of God, which I imagine rules out papists, and indicates that the authors are Fifth Monarchists or groups associated with them. Internal evidence suggests two of the letters come from Abingdon, which also indicates a seditious origin to the letters.”

He nodded. “And your conclusions?”

“That the matter should be looked into.”

“Is that all? That seems very casual.”

“The letters themselves prove nothing. Had I written them, and been arrested, my defense would be that they were all to do with my cousin’s wedding.”

Mr. Bennet snorted.

“Far be it from me to give you advice, sir, but precipitate haste might be troublesome. I assume that you obtained these letters by occult means?”

“We have an informant, that is correct.”

“So if you swoop, your informant will be of no further use to you, as it will be obvious you knew where to look. Look, sir, it is more than likely that these letters indicate that a rising of some sort will happen, and that it will be in several parts of the country, led from the capital.”

“That is what concerns me,” he said.

“Use your informant to find out where the provincial risings are to be, and on January eleventh, move troops there. I take it the king does have troops he can count on?”

“No more than a few thousand can be trusted absolutely.”

“Use them. As for London, sit back and watch; find out who is involved and how many, and have troops ready. Make sure the court is guarded. Then let the rising happen. Cut off from any support it will be easy to put down, and you will have solid evidence of treason. You may then act as you please. And collect such praise as will be your due for your prompt action.”

Bennet leaned back in his seat and watched me coldly. “My aim is to guard the king, not to gather praise.”

“Of course.”

“For a cleric you seem to have a remarkable grasp of these matters. It may be that you were in deeper with Mr. Thurloe than I suspected.”

I shrugged. “You asked my advice, and I gave it. You do not have to take it.”

He had not dismissed me, so I sat there while he stared out of the window before pretending to notice me again.

“Go away, sir,” he said tartly. “Leave me in peace.”

I did as ordered, and left thinking that I had not succeeded in disarming a man who could do me very considerable harm, and that my tenure at the university would be shortlived. I resigned myself to this as best I could; I was wealthy enough through my mother’s side and had no fear of starvation or penury but, nonetheless, I liked my position and the stipend it brought, and had no desire to relinquish it.

I had played my cards as well as I could. The great virtue of deciphering letters is that it is profoundly difficult for anyone else to say whether you have done it correctly. In this case the interpretation (allied to a certain knowledge of my own) enabled me to demonstrate my potential usefulness at no great cost. For the letters clearly indicated that the uprising which so exercised Mr. Bennet was, in fact, going to be little more than the screaming and yelling of a few dozen fanatics and could in no way threaten the king. This band might believe that, with God’s help, they could take London, the country and perhaps even the entire world; I saw fairly clearly that their so-called rising would be farcical.

But, with a little prodding from Bennet, as I later learned, the government took it seriously, and began having nightmares about the bitter and unpaid remnants of Cromwell’s army rising all over the country. In late January (such is the length of time it takes to get information from London to Oxford in winter) news began to come through that Thomas Venner’s band of Fifth Monarchist maniacs had fallen into the trap so skillfully set for them and been arrested after creating a stir that had lasted for all of five hours. More, a sudden decision had led the government to station a squadron of cavalry at Abingdon and in half a dozen other places a few days before, and to this wise move was attributed the fact that the old soldiers there had remained quiescent. In my opinion they had never considered doing anything at all, but no matter; the effect was made.

Five days after I heard of all this, I received a letter summoning me to London. I went there the following week and was instructed to visit Mr. Bennet, who had now been permitted to move into accommodations in Whitehall where he was so much closer to the king’s ear.

“I imagine you have heard of the monstrous treason which the government successfully repressed last month?” he said. I nodded.

“The court was mightily alarmed,” he went on. “And it has shaken the confidence of many. Including His Majesty, who can no longer hold on to the illusion that he is universally beloved.”

“I am distressed to hear that.”

“I am not. There is treason everywhere in this country, and it is my job to stamp it out. At least now there is a chance that someone might listen to me when I give warnings.”

I sat silently.

“When we met last, you gave me certain advice. His Majesty was impressed by the speed with which the rising was put down, and I was pleased to have talked over my policy with you.”

Which, roughly translated, meant that he had taken all the credit and that I should bear in mind that he was my sole conduit to royal favor. It was kind of him to spell it out so clearly. I nodded.

“I am glad to be of service. To you and His Majesty,” I said.

“Here,” he said, and handed me a piece of paper. It contained a document confirming the king’s trusty and well-beloved servant John Wallis in his post as Professor of Geometry at the University of Oxford, and another, appointing the same trusty and well-beloved John Wallis as Royal Chaplain to the king, at a salary of two hundred pounds a year.