Vasco nodded as if he understood. He does have a certain low animal cunning. “Algol doesn’t use numbers.”
“No, he uses twenty-three letters, and if he is pairing them up he has hundreds of couplets available. So the first thing the Maestro asked was if Sciara’s gnomes had checked for couplet frequency. Perhaps GX stands for A, NT for B, EO for King of France, understand? Now you pass me the notes and I’ll tell you what to look for in the ciphertext and if we’re quick about it we may have this thing broken before the Maestro comes.”
“And if we’re really lucky, angels may appear to transport you to Paradise.”
I thought that was the end and the pleasure of refusing me had overridden his duty, but then he shrugged and opened the satchel. He held out the work notes, making me stand up to reach them.
“So what do I look for?” he asked.
“My initials. LAZ, for Luca Alfeo Zeno. How many times can you see those letters together? I know they appear more often than they should.” I set to work reading what Sciara’s team had tried, ignoring more scoffing from Vasco.
Sciara’s notes were thorough and detailed. I learned that the ciphertext comprised four Algol dispatches, varying in length from three pages to nine, twenty-four pages in all. The Ten’s cryptologists had tested for letter frequency and couplet frequency and even “word” frequency, although the five-letter groups could not be real words. Their conclusion was that the distribution of letters was not truly random, but not skewed enough for a substitution cipher, such as a Caesar, or a transposition cipher, which is a gigantic anagram. They suspected that all four dispatches had been written using the same code, so very likely it was a nomenclator.
They had not tested for triplets, though. Of course my own initials in a page of meaningless text will always jump out at me, and the previous evening I had seen them twice on one page when I was looking over the Maestro’s shoulder. After a few minutes of angry muttering, Vasco announced that he had found my initials seven times, and at least once in each of the four dispatches. We had grasped a thread in the labyrinth! That ought to lead somewhere.
But where? There were thousands of other three-letter combinations to look for, and the only sensible next move I could think of was to hand the problem back to Sciara and tell him to put his legions to work on triplet frequencies. I suggested we each try to find another repeating triplet.
Eventually the thump of the Maestro’s staff on the terrazzo outside announced his approach and Vasco hastily vacated his chair. The old man came hobbling in, looking murderous.
“Make any sense of it?” he growled at me, with a wave at the slate table.
“Nine words,” I said. “That’s all.”
He grunted, meaning that he had reached the same conclusion.
“And my tarot doesn’t work either.”
He seemed unsurprised. “Why do you think he’s called Algol? Vizio , who named the unknown that and why?”
“I have no idea, Doctor.”
More grunt.
I doubted that Algol would turn out to be a true ghoul, a monster that haunts graveyards and eats corpses, but he might well be a demonologist, and the laws of demonology dictate that anyone who employs demons will soon find that the shoe is on the other hoof and the demons are employing him.
Vasco was looking puzzled. I thought it kinder to leave him that way.
“Can you break a nomenclator in an unknown language?” I asked.
The Maestro’s scowl darkened. “Given time and enough text to work on, yes. But there are far more good ciphers than good people using them. When a cipher is broken, it is almost always because the operator was careless. Human error damns us all! If we look hard enough and long enough, we will find that he has made a mistake somewhere.”
That was my cue. “He likes my initials. He used them seven times.”
The effect on the Maestro was dramatic. He sat up straight and his eyes blazed with excitement. “Where? Show me!”
Two minutes later he snapped, “Bring me the pastels!”
I fetched our box of pastels.
We marked every LAZ in red. After another ten minutes or so we had located and highlighted four more triplets that were repeated at least once. Nostradamus told me to round up the three oldest Angeli children currently available. Reading and writing are uncommon skills among the citizen class, but I taught Mama and she teaches all her children.
Archangelo was on a ladder, dusting the tops of high pictures in the salone, and so was happy to be recruited. Corrado and Christoforo happened to come running up the stairs as I emerged from the atelier and were not, but they brightened when I chivied them into the dining room and they saw the pile of shiny soldi in front of the Maestro. Most of the time he is as tight as a coffin lid where money is concerned, but he has little idea of how much it means to adolescents and often tips them extravagantly.
He handed out a pastel crayon and four or five pages of ciphertext to each of us. He explained the rules. The boys received a soldo for each new repetition they found. Vasco and I did not. The vizio was clearly torn between the excitement of the chase and regarding this labor as far beneath the dignity of a major officer of the Republic-which he is not, but likes to think he is.
The pile of coins shrank rapidly. We found ten different triplets that were repeated. None of the others repeated as often as my initials did, and most only once. My initials were always in the middle of the five-letter groupings, and the others usually had their own places also, with a couple of exceptions that could easily be due to chance. Archangelo found a four-letter repeat and was rewarded with two soldi.
Whatever we were discovering was a clue to analyzing the cipher and might even lead us to breaking it, so I grew quite excited. The Maestro became crabbier and crabbier until he slapped his hand on the table and said, “Stop!”
Surprised, we all stopped.
“This is a waste of time. Off you go, boys, thank you. Vizio, please gather up the papers. Alfeo, has that freeloading friend of yours removed his belongings yet?”
“He was never a friend of mine,” I protested. “He had no baggage with him when he left this morning.”
“Then pack up his things and take them to Ca’ Sanudo and tell him to find someone else to sponge off!”
It was almost noon. I had hoped to call on Violetta, but I was lacking several hours’ sleep and might well have settled for a siesta instead.
“After dinner?”
“No, now! The vizio is our guest and that simpering pretty boy is not. I want him out of here.”
“I don’t mind sleeping on the couch,” Vasco said, with the martyrdom of a triptych saint. “I can guard the house better there.”
The Maestro ignored him. “You heard me,” he snapped.
I sighed. “Your wish is my command, Oh Most Illustrious Master!”
Although Nostradamus has uncommonly small hands, they have always packed a lot of sleight, and when Vasco tucked his papers back in his satchel, he didn’t think to count them.
11
I laid Danese’s admirable, expensive leather portmanteau on the spare room bed and began to pack it with Danese’s admirable, expensive silken garments. Eva had been generous to her hired lover. He owned luxuries I had never seen before-scented soap and a pearl-handled razor. He had no less than three spare pairs of shoes. One shoe was perceptibly heavier than the other five, though, a phenomenon I soon tracked down to a roll of gold coins tucked in the toe. Faced with a large sum of money and only my own honesty to defend me against later charges of pilfering, I decided to count it, and made it 60 sequins, equal to 165 silver ducats. That is a lot of money. Either Eva had been insanely generous to her hired lover or Danese had been working something on the side. Even I, in my boyish innocence, could think of several possibilities. I put the coins back in the shoe and the shoe in the case.