The Rule of Four by Ian Caldwell, Dustin Thomason

it, my father believed it must be found outside the book: in diaries, letters, family documents. He never told me as much, but I think he always suspected that there
was
a great secret locked inside the pages. Against Taft’s formulations, though, my father felt it was a secret about love: an affair between Colonna and a woman below his station; a political powder keg; an illegitimate heir; a romance of the kind teenagers imagine before the ugly bride of adulthood comes and snuffs out childish things.

    However much his approach differed from Taft’s, though, when my father arrived in Manhattan for a research year away from the University of Chicago, he sensed that the two men were making great strides. Curry insisted that his old friend join them in their work, and my father agreed. Like three animals in a single cage, the men struggled to accommodate one another, circling in suspicion until new lines were drawn and new balances struck. Nevertheless, time was their ally in those days, and all three shared faith in the
Hypnerotomachia
. Like a cosmic ombudsman, old Francesco Colonna watched over and guided them, whitewashing dissent with layers of hope. And for a while, at least, the veneer of unity endured.
     
    For more than ten months, Curry, Taft, and my father worked together. Only then did Curry make the discovery that would prove fatal for their partnership. By then he had gravitated out of the galleries and into the auction houses, where the larger stakes of the art world lay; and it was as he prepared his first estate sale that he came across a ragged notebook that had once belonged to a collector of antiquities, recently deceased.
    The notebook belonged to the Genoese portmaster, an old man with a crabbed hand who made a habit of remarking on the state of the weather and his failing health, but who also kept a daily record of all goings-on at the docks in the spring and summer of 1497, including the peculiar events surrounding the arrival of a man named Francesco Colonna.
    The portmaster—whom Curry called Genovese, for he never gave his name—gathered the rumors about Colonna circling through the wharf. He made a point of overhearing the conversations Colonna had with his local men, and learned that the wealthy Roman had come to Genoa to oversee the arrival of an important ship, whose cargo only Colonna knew. Genovese began bringing news of incoming ships to Colonna’s day lodgings, where he once caught Colonna scribbling notes, which the Roman hid as soon as Genovese entered.
    Had it been left at that, the portmaster’s diary would’ve shed little light on the
Hypnerotomachia.
But the portmaster was a curious man, and as he grew impatient waiting for Colonna’s ship to arrive, he sensed that the only way to discover the nobleman’s intentions was to see Francesco’s shipping documents listing the contents of the cargo. Finally he went to ask his brother-in-law, Antonio, a merchant who sometimes trafficked in pirated goods, if a thief might be hired to enter Colonna’s lodgings and copy whatever could be found there. Antonio, in exchange for Genovese’s help in another shipping scheme, agreed to help.
    What Antonio found was that even the most desperate men would refuse the job upon mention of Colonna’s name. The only one willing to do it was an illiterate pickpocket. As it happened, though, the pickpocket did his job well. He copied all three documents in Colonna’s possession: the first was part of a story, which the portmaster found of no interest and never fully described; the second was a scrap of leather with a complicated diagram drawn on it, which was inscrutable to Genovese; and the third was a peculiar sort of map, consisting of the four cardinal directions, each followed by a set of units, which Genovese struggled in vain to understand. The portmaster was beginning to regret hiring the thief, when an event transpired that quickly made him fear for his life.
    Upon his return home at night,