The Rule of Four

The first night Katie noticed I couldn't sleep, she recited a work by her favorite author for me, and I followed Curious George to the ends of the earth, where the weight on my eyelids carried me off. After that, there were many nights I tossed and turned, and Katie found a solution for each of them. Late-night episodes of M*A*S*H; long readings from Camus; radio programs she used to listen to at home, now caught on a faint transmission down the coast. We left the windows open sometimes, to hear the rain in late February, or the conversations of drunk freshmen. There was even a rhyming game we invented for empty nights, something Francesco Colo

There once was a man named Camus, I would say, leading her.

When Katie smiled at night, she was like a Cheshire cat in the dark.

Who left U. Algiers with the flu, she would respond.

He had lots of potential.

But was not existential.

Which made old Jean-Paul Sartre so blue.

But for all the ways Katie had found to make me sleep, the Hypnerotomachia still kept me awake more often than not. I'd figured out what the smallest harmony of a great victory was: in Rithmomachia, where the goal is to establish number patterns containing arithmetical, geometric, or musical harmonies, only three sequences produce all three harmonies at once-the requirement for a great victory. The smallest of these, the one Colo

Paul quickly took the numbers and made a cipher of them. He read the third letter, then the fourth after that, followed by the sixth and ninth, from the appropriate chapters; and within an hour, we had another message from Colo

I begin my story with a confession. In the keeping of this secret many men have died. Some have perished in the construction of my crypt, which, imagined by Bramante and executed by my Roman brother Terragni, is an unequalled contrivance for its purpose, impervious to all things, but above all to -water. It has taken many victims, even among the most experienced men. Three have died in the movement of great stones, two in the felling of trees, five in the process of building itself Others of the dead I do not mention, for they have perished shamefully and will be forgotten.

Here I will convey the nature of the enemy I face, whose rising power lies at the heart of my actions. Reader, you will wonder why I have dated this book 1467, some thirty years before I wrote these words. It was for this reason: in that year the war began which we are still fighting, and which we are now losing. Three years earlier His Holiness, Paul the Second, fired the court abbreviators, making clear his intentions toward my brotherhood. Yet the members of my uncle's generation were powerful men, with much influence, and the expelled brethren flocked to the Accademia Romana, which good Pomponio Leto sustained. Paul saw that our number persisted, and his jury increased, hi that year, 1461, he crushed the Academy by force. So that all would know the strength of his determination, he imprisoned Pomponio Leto, and had him accused as a sodomite. Others of our group were tortured. One, at least, would die.

Now we are challenged by an old enemy, suddenly reborn. This new spirit grows in strength, and finds a more powerful voice, so that I have no choice but to construct, with the assistance of friends wiser than I, this device whose secret I disguise here. Even the priest, philosopher though he may be, is not equal to it.

Continue, reader, and I will tell more.

The court abbreviators were the humanists, Paul explained. The pope thought humanism bred moral corruption. He didn't even want children to hear the works of the ancient poets. Pope Paul made an example of Leto. For some reason, Francesco took it as a declaration of war.

Colo

When did Eratosthenes make that calculation? I asked.

Around 200 b.c.

That sealed it.

I think you're wrong, I said. All the riddles so far have to do with Renaissance knowledge, Renaissance discoveries. He's testing us on what humanists would've known in the 1400s.

Moses and comma had to do with linguistics, Paul said, trying on the idea for size. Correcting faulty translations, like what Valla did with the Donation of Constantine.

And the Rithmornachia riddle had to do with math, I went on. So Colo

It was only when Paul looked so surprised by the clarity of my thinking that I realized how my role had changed. We were equals now, partners in the enterprise.

The two of us began meeting at Ivy each night, back in those days when he kept the President's Room in better shape, expecting Gil to check up on him at any minute. I ate di

But the night after I missed my third morning run, all of that changed. I was on the cusp of a solution to the riddle, I thought, when by sheer accident she realized how I was spending our hours apart.

This is for you, she said, letting herself into our room in Dod.

Gil had left the door unlocked again, and Katie no longer knocked when she thought I was alone.

It was a cup of soup she'd brought me from a local deli. She thought I'd been holed up with my thesis this whole time.

What are you doing? she asked. More Frankenstein?

Then she saw the books spread out around me, each with some reference to the Renaissance in the title.

I never thought it was possible, to lie without knowing it. I'd strung her along for weeks on a raft of pretexts-Mary Shelley; insomnia; the pressures we were both facing, which made it hard to spend time together— and eventually it carried me away, drifting from the truth so slowly that the distance each day seemed no greater than the last. She knew I was working on Paul's thesis, I thought; she just didn't want to hear about it. That was the arrangement we'd come to, without ever having to say it.

The conversation that followed was all silences, hashed out in the way she looked at me and I tried to hold her stare. Finally, Katie put the cup of soup on my dresser and buttoned her coat. She looked around the room, as if to remember the details of where things stood, then returned to the door and locked it before letting herself out.

I was going to call her that night-as I knew she expected me to, when she returned to her room alone and waited by the phone, the way her roommates later told me she did-except that something got in the way. Fantastic mistress, that book, flashing leg at all the right times. Just as Katie left, the solution to Colo

The horizon in a painting was the solution: the point of convergence in a system of perspective. The riddle wasn't about math; it was about art. It fit the profile of the other puzzles, relying on a discipline peculiar to the Renaissance, developed by the same humanists Colo