The Last Secret of the Ark

by James Becker

  In the morning, they got up about an hour earlier than usual and sat down to a typical French continental breakfast in the hotel dining room.

  ‘More coffee?’ Bronson asked, picking up the metal jug that he’d just used to top up his own cup.

  ‘Full to the brim, please,’ Angela replied, buttering a final slice of baguette and adding a spoonful of raspberry jam. ‘The caffeine might jog my brain into some kind of useful activity.’

  ‘That’d be a bonus. And there’s one small pain au raisin left if you want it.’

  ‘No. You eat it, then we must get back upstairs. We’ve got work to do.’

  Back in their room. Angela sat at the desk and opened her laptop while Bronson lay full-length on the bed. He claimed that lying flat helped him think, which Angela didn’t entirely believe, but in reality there was nowhere else in the room for him to sit. Or lie.

  ‘So how far have we got?’ he asked.

  ‘Roughly or exactly?’

  ‘Either or both.’

  ‘Nowhere,’ she replied. ‘Nada. Zilch. We’ve made no progress whatsoever.’

  ‘One of the problems is that we still don’t know when the document was written,’ Bronson said. ‘There are no clues on it, but I still think it was probably composed in the thirteenth century, round about the time the siege of Montségur ended.’

  ‘That’s my guess as well, and if that dating is right, it’s most likely that the plaintext will have been written in Occitan rather than Latin or French. And that,’ Angela went on, ‘leads to another rather more complicated complication. I didn’t know until I started doing research that there’s no standard Occitan language in written form. There are different versions based on various dialects, so when we do crack the cipher it might still take a while to work out what the Occitan text means. And because today it’s a very minor and virtually dead language, there isn’t an online translator we can use.’

  ‘I have seen a few online Occitan dictionaries,’ Bronson said, ‘so they should give us an idea of what individual words mean, and we could probably feed phrases into Google Translate and tell the program they’re Catalan. That might work. You’ve told me the two languages are pretty similar. If we get really stuck, I suppose we could bung the Occitan over to one of your linguist chaps at the museum and ask him to translate it for us. But the first thing we should do is find out the letter frequencies in Catalan.’

  ‘Give me a minute,’ Angela said, ‘and I’ll check it out.’

  She opened up a search engine, typed a few words and then studied the results the program displayed.

  ‘It’s not as clear-cut as I was hoping. According to this website, the commonest six letters in Catalan, in order, are E A S R L T. The letters E and A both occur about thirteen per cent of the time, with E being slightly more common. The letter S is found much less frequently, only about eight per cent, and then R, L and T are all around the six per cent mark, as are the next dozen or so letters. So if we assume a single transposition cipher was used and we do a frequency analysis based on this information, the two commonest letters found would probably represent E and A, but with no way of telling which is which. I don’t think that’ll get us very much further, but we can try it if you want.’

  ‘We might as well, I suppose. I’ll note the letter frequencies if you read through the text.’

  Bronson took a sheet of paper and a pencil and wrote out the letters of the alphabet in a column down the left-hand side. As Angela read out each letter of the ciphertext, he placed a vertical stroke against that letter, with a diagonal line through each group of four occurrences to make it easier to count the total.

  ‘You were right,’ he said when they’d finished. ‘There are some letters that don’t appear at all, and a handful that occur with roughly the same frequency. But what I don’t see are any letters that are so common they could represent E or A, or even S.’ He walked over to Angela and handed her the sheet. ‘Maybe you can see something I can’t.’

  Angela scanned what he’d written and shook her head.

  ‘No, nothing jumps out at me. The other problem is that the ciphertext is a very small sample. Frequency analysis works best with large blocks of text. So what do we do next?’

  ‘I don’t like making assumptions,’ Bronson replied, ‘but sometimes you really do have no other choice. So let’s assume that this text was encrypted around the mid thirteenth century, and that it was done by someone in the Languedoc area of France. That implies that the language used was Occitan because that’s what they were speaking at that time in that part of the country. I think we can also assume that whoever encrypted the text was either a Cathar or somebody very closely associated with them. If we take those as givens, and as we’re probably not dealing with a simple Atbash or Caesar cipher but something more complex, maybe this document was encrypted using keywords or a key phrase, and employed something like a very basic double substitution system.’

  ‘You need to explain that.’

  ‘Okay. What I’m wondering is whether the person who did this used a kind of variant of the Atbash system. With Atbash you write out the alphabet, and then underneath it you write out the alphabet again, but backwards. so that Z is below A, or perhaps forwards but shifted a number of spaces to the left or right. Or backwards and shifted. Those are the only possible variants. But it would have been obvious to anybody using Atbash, even then, that each plaintext letter was always going to be represented by the same letter in the ciphertext, no matter whether they used the alphabet or some phrase. So maybe they thought of a wrinkle, a way to make it more difficult to crack.’

  ‘Like what?’

  ‘Well, something like having two ciphertexts underneath the alphabet, or one above and one below, so that they had two letter choices for each plaintext letter by alternating the use of the ciphertexts. Then frequency analysis wouldn’t work, and you’d need to know both ciphertexts to decode it.’

  Angela thought about that for a few seconds, then shook her head.

  ‘Let’s take a couple of steps back,’ she said. ‘That page of text was encoded for a reason, obviously. Now, if it was a secret that the writer didn’t want to ever be revealed, then the obvious thing he could have done was nothing. No paper, no encryption, and the secret would be safe forever. But he didn’t do that. Therefore, thinking about it logically, his intention must have been to encrypt it in a way that would allow it to be deciphered at some future date.’

  ‘That makes sense. So he must have assumed that whoever wanted to decipher it would have known how to do it, and that could mean something like using a phrase or piece of text that every Cathar would know, for example.’

  ‘Exactly. Either that or he would have left some clue on the page itself to suggest what the ciphertext should be. It had to either be common knowledge amongst the Cathars or a clue to the decryption process had to be provided.’

  They both stared at the copied sheets of paper in front of them, seeking inspiration.

  ‘Right,’ Bronson said. ‘I don’t see anything on the sheet that could be a clue. The only odd feature, apart from the fact that we can’t read it, is that a couple of the lines of text have been underlined, and I can’t see how that is in any way significant. Maybe those two sentences are particularly important, but we won’t know why until we’ve deciphered it.’

  Angela looked puzzled.

  ‘I’ve looked at a lot of medieval manuscripts,’ she said, ‘and I can’t recall ever seeing one where two whole lines of the text was underlined like this. Underlining has been used for thousands of years to link words together or add emphasis. But this looks different. Maybe they’re dividers.’

  Bronson shrugged. ‘Perhaps. But we won’t know until we’ve cracked the encryption. Let’s look at phrases or sentences important to the Cathars. Do you know if they had prayers or rituals that every Cathar would know but a non-Cathar wouldn’t?’

  ‘I’ll check,’ Angela replied, and started another Internet search. ‘Oka
y,’ she said after a few moments, ‘the first thing is that the word “Cathar” was derogatory, meant to be a kind of insult. They called themselves bons hommes – “good men”, meaning good Christians – but that’s too short to use as part of the ciphertext key.’

  ‘We need something a lot longer,’ Bronson said. ‘What about a prayer? If you ask a Christian – or even an atheist or agnostic – to recite a prayer, the one they all know because it’s drummed into them at school is the Lord’s Prayer. Did the Cathars have something similar?’

  ‘Hang on a minute. Right, there’s one authentic Cathar liturgy that’s survived the years. There are two versions of it, one written in Latin and the other in Occitan. The Latin version is called the Cathar Ritual and the Occitan one is the Lyon Ritual. I don’t know why it has two names because the text is the same. Only the languages used are different.’

  ‘Yes, but a liturgy is a church service, isn’t it, with a priest saying something and the congregation responding, and they probably had lots of them. Was that their most important liturgy, or was it the only one that’s survived? If it was one of dozens, it wouldn’t be important enough to use a line from it as an encryption key.’

  ‘Pass. I’ve no idea how important it was, and that’s a good point. Let me find out if they had a special prayer.’

  She changed the search terms slightly and accessed a different website. She read what the site told her and then started to laugh.

  ‘What?’

  ‘You know what you were saying about everybody knowing the Lord’s Prayer? Well, the Cathars had a prayer called the Pater Noster, and it’s the same prayer, except that it’s in Latin. In fact, according to this site it’s probably the oldest prayer in existence and was allegedly created by Jesus. Some of the phrases in it are found in Jewish prayers, and the earliest versions were written in Greek.’

  ‘Not Hebrew?’

  ‘Oddly enough, no. In the first century the lingua franca of most of the Roman Empire was Koine – that means “common” – Greek, so virtually all Christian writings of the period were in that language. Some scholars believe parts of the New Testament were originally written in Hebrew or Aramaic and then translated into Greek, but there isn’t any evidence for that. According to this site, it’s more likely that translations went the other way, from Greek into Aramaic. But the Old Testament was different. That was written in Hebrew, and we know that because some very early versions were discovered back in 1947 among the Dead Sea Scrolls.’

  She connected her portable inkjet printer, fed a sheet of paper into it and printed what she’d found. Then she passed the sheet to Bronson, who read aloud from it, stumbling over some of the Latin words.

  Pater noster qui es in cælis, sanctificetur nomen tuum; adveniat regnum tuum.

  Fiat voluntas tua sicut in cælo et in terra.

  Panem nostrum supersubstancialem da nobis hodie.

  Et dimitte nobis debita nostra sicut et nos dimittimus debitoribus nostris.

  Et ne nos inducas in temptationem sed libera nos a malo.

  Quoniam tuum est regnum et virtus et gloria in secula.

  Amen.

  ‘You know,’ he said, ‘this might be it. That first line’s got about sixty characters in it, so if the man who encrypted this wrote out the alphabet and then that first sentence on the two lines underneath, that would give him two ciphertext letters for each letter of the alphabet. It wouldn’t really be a polyalphabetic cipher, just something a bit more secure than a single substitution version.’

  Angela nodded. ‘Let’s give it a go.’

  Chapter 21

  Paris, France

  The first thing Lemuel Dayan did that morning when he walked down the Rue Serpente and into the Rue Danton was to look up.

  He had no interest in the architecture of the buildings that lined the streets, but he was looking for something that most of them didn’t seem to possess – a security camera. Unlike London, where almost every street corner, house and shop was festooned with CCTV cameras of various sizes and types, in that particular area of Paris he initially saw none. Perhaps there was a local law that forbade the mounting of such devices on the façades for aesthetic reasons, though the way French architects were capable of designing and building hideously ugly structures that were entirely out of keeping with the surroundings made this seem unlikely. Or perhaps it was just a low-crime area.

  He finally got lucky in a small shop on the corner of the Rue Mignon, almost opposite the Maison de la Recherche. There was a small black camera positioned inside the glass door of the shop, clearly intended to record anyone who approached the establishment, but from the angle of it Dayan thought it might cover some of the street outside and the intersection. And beyond that was the target building.

  He stepped inside the shop, reached into his jacket pocket and extracted a light blue plastic card with the words ‘INTERPOL IDENTIFICATION CARD’ in the top left-hand corner above a colour photograph of his face, and with his personal details printed on the right. The genuine articles were machine-readable smart cards, but at a casual glance what Dayan had looked real enough, and because almost no civilian ever saw either a real Interpol card or a real Interpol officer, the chances of it being recognised as a fake were almost nil.

  ‘I wonder if you could help me,’ he began, replacing the card in his wallet after the middle-aged male shopkeeper had stared at it for a few seconds. ‘We’re running a surveillance operation in this area looking for a particular person. He might have walked down this street and he could have been detected by your camera.’ He pointed back towards the door. ‘Could I take a copy of your surveillance tape for one specific date?’

  He took out a small notebook and read out the date on which Gellerman had told him the ‘Italian professor’ had visited the Bibliothèque Serpente. Fifteen minutes later, he walked out with a copy of that day’s camera recordings stored on the external hard drive in his pocket.

  He found two other shops with similar security arrangements in the surrounding streets. Both were further away from the library but both were situated on possible routes to and from the building, so it was worth copying the videos.

  * * *

  While Lemuel Dayan was looking for security cameras, Josef Gellerman had taken up temporary residence in a cafe at the end of the Rue Danton, where it merged into the Place Saint-Michel. He’d chosen a table that offered a clear, albeit distant view of the Maison de la Recherche, though the main door of the building was out of sight. If he’d guessed right, that shouldn’t matter. He had ordered a café au lait and a small basket of pastries and settled down for what might be a long wait.

  In fact, he’d only been there for about three quarters of an hour when he saw George Anderson step out of the building and start strolling towards him. He’d paid for his drink and food when it had been delivered, so he left a few coins as a tip, ate the last corner of a croissant and then left the cafe.

  He intercepted the English academic before he reached his destination.

  ‘Mr Anderson,’ he said quietly, stepping in front of the man and forcing him to stop.

  Anderson looked puzzled for a few moments, but then his expression changed and recognition dawned.

  ‘Ah, it’s Mr Mahler, isn’t it?’ he said.

  ‘It is,’ Gellerman responded, ‘and I have a small problem that I know you can help me with.’ He steered Anderson over to one side of the pavement, away from most of the pedestrians.

  ‘Look, I’m just on my way out for lunch so this isn’t a very convenient time,’ Anderson said. ‘Could you see me in the library this afternoon?’

  Gellerman shook his head. ‘I really am in a hurry and this won’t take more than a few minutes. And I promise it will be worth your while to help me out.’

  ‘Oh, very well,’ the academic replied. ‘What is it?’

  ‘It’s really about you. You see, when I asked you about the policy of the library on copying documents, I don’t think you were truthful. I don’t be
lieve that an important library, part of the Sorbonne, would accept documents of potential historic importance and then just dump them in a reading room somewhere for anybody to paw through without first making copies. But that’s what you told me had happened with the Hautpoul folio and that’s why two important pieces of paper went missing from it. I think you were lying to me. I believe the library would have made copies of all those documents as soon as they arrived, and only after that had been done would anybody have been allowed to study them. To me, that would make more sense.’

  Gellerman’s gaze didn’t waver from Anderson’s face and the Englishman’s change of expression was easy enough to read. But before he could respond, the Israeli ploughed on.

  ‘I don’t want to make this difficult,’ he said, ‘and if we both go back to the Bibliothèque Serpente right now and you obtain copies of those two missing documents for me, then I’ll walk out of your life forever.’

  ‘If you come back this afternoon—’ the Englishman began.

  ‘No, right now,’ Gellerman interrupted. ‘I said I would make it worth your while, so let me just explain what I meant. If you hand me those two copies within the next ten minutes, you can go off and enjoy your lunch at one of these cafes. If you don’t agree to do this, I will break both of your arms right here and right now. Believe me when I say that I have done this kind of thing many, many times before and there would be nothing you could do to stop me. It would take me less than ten seconds. A very painful and life-changing ten seconds for you.’

  The Israeli could see the blood draining from Anderson’s face. The man was an elderly academic, and in all probability the last time he had engaged in any kind of physical conflict would have been almost a half-century earlier on the playing fields of whatever school he had attended back in England.

  ‘I understand,’ Gellerman went on in the same conversational tone, ‘that the French medical system is very good, with competent and caring doctors and nurses, but you would have an extremely unpleasant few minutes waiting for an ambulance to arrive. Then you’d have to spend about a week in hospital having your arms sorted out, and after that there would be weeks of convalescence and physiotherapy, not to mention the very real possibility of suffering aches and pains for the rest of your life.