How much did I know, at that time, about the so-called Corpus hermeticum? No more, I suppose, than anyone else. I was aware, naturally, of how the manuscripts first appeared in Florence some two hundred years ago, after Cosimo de' Medici sent forth bands of his agents with orders to bring back to his magnificent library whatever parchments they could lay their hands on in every church and monastery that would let them past their doors. And I knew how these explorers-mostly monks from the San Marco in Florence-had recovered scores of lost masterpieces in the fusty libraries and scriptoria of the far-flung monasteries of Monte Cassino, Langres, Corvey and St. Gall, works by such esteemed authors as Cicero, Seneca, Livy and Quintilian, and dozens more besides, all of which were quickly edited, translated and placed for study and safekeeping with the other treasures in the Medici Library. The thought of these scholar-explorers, these intrepid friars on muleback, I had always found appealing. Theirs were the humblest and yet most noble voyages of discovery, dangerous trips made decades before the sailing of Columbus and Cabot, before the mania for navigating the world took over, perilous journeys whose object was not gold or spices or trade routes but ancient manuscripts, a few dried-out animal skins whose secret worlds were brought back to life only after weeks of plodding along overgrown, bandit-infested mountain tracks.

And I knew, finally, how the greatest of all these discoveries was made in or about the year 1460, less than ten years after the fall of Constantinople to the Turks, when one of Cosimo's fearless monks brought back to Florence the first fourteen books of the Corpus hermeticum. The treasure uncovered in Macedonia was as valuable-or so Cosimo believed-as the spices of India or the gold of Peru, and worth all of the other manuscripts in the Medici Library combined. The parchments reached Florence soon after the untranslated dialogues of Plato, which had been brought out of Macedonia by Giovanni Aurispa. But Cosimo ordered Marsilio Ficino, the greatest scholar in Florence, and therefore the greatest scholar in the entire world, to translate the works of Hermes first, because he believed, like everyone else, the great Ficino included, that Plato had received all of his wisdom from none other than the ancient Egyptian priest Hermes Trismegistus. For, after all, had not ancient scholars like Iamblichus of Apamea described how Plato drank down the revered knowledge of Hermes Trismegistus while visiting Egypt? So why should Cosimo read copies by this upstart Plato if he owned their originals, the works of Hermes Trismegistus himself?

As Ficino busily translated the fourteen books from Greek into Latin there arose in Florence and then throughout the rest of Europe dozens of rumours about the existence of more Hermetic manuscripts, in Macedonia and elsewhere, all still awaiting discovery. Some twenty more parchments were eventually recovered, after much bribing of priests and ransacking of temples, but all were versions or fragments of the same fourteen books, and three more besides, so that the total number of Hermetic texts in existence stood at seventeen. A century after Cosimo's death, the Greek text of the Macedonian parchments was published in Paris, and afterwards both copies of the Corpus hermeticum-the one Latin, the other Greek-went through many editions and emendations, all of which Sir Ambrose had, it seemed, dutifully collected: as many editions and translations as were printed throughout Europe in the past two hundred years.

Alethea had beckoned me forward to the shelves to show how her father owned the editions prepared by Lefèvre d'Étaples, Turnebus, Flussas, Patrizzi, Rosseli, even Trincavelli's edition of Johannes Stobaeus, a Macedonian pagan who had collected together some of the Hermetic works more than a millennium earlier. But none of these collections, she claimed, contained the eighteenth manuscript, The Labyrinth of the World, the first Hermetic text discovered in almost two hundred years.

I had watched sceptically as she stood beside the shelf and ticked them off one by one, thinking what a pity it was that, on these volumes at least, Sir Ambrose had wasted so much money. All were handsomely bound, it was true, and I could have sold most of them in a matter of days to any one of a dozen collectors. But fifty years ago the great Isaac Casaubon had demonstrated how the entire Corpus hermeticum-this supposed fountainhead of the world's most ancient magic and wisdom-was nothing more than a fraud, the invention of a handful of Greek scholars living in Alexandria at some time in the century after Christ. So of what possible value or interest for anyone was one more book, one more of these fakes?

The coach forded the thin stream, its wheels tossing curtains of water to either side. The down payment gold sovereigns-an even dozen of them-chimed softly in my pockets. I closed my eyes and didn't open them, for all I remember, until we reached the smoke of London, which I swear had never smelled so good.

Chapter Eight

The battle for Prague lasted less than an hour. Frederick's soldiers and their feeble earthworks were no match for the Imperial hordes with their 24-pound cannon-balls and flintlock muskets. The artillery ripped apart the trenches in front of the Summer Palace, then the musketeers went to work, balancing their weapons on forked rests and firing on the Bohemian infantry skidding and tumbling down the hillside. Those who escaped the musket-balls were cut down by the sabres of the cavalry who came sweeping through the game park on their war-horses a few minutes later. Those who escaped the cavalry spilled through the gates and into the castle or, failing that, leapt into the Vltava. They tried to swim the river at its bend, hoping to reach the Jewish Quarter or the Old Town, to put water between themselves and the rampaging enemy.

Others too were trying to escape across the Vltava. A convoy of overloaded coaches drawn by mules and dray-horses was jostling three abreast on the bridge, stretching all the way across the river and filling Charles Street as it wound its narrow channel through the rows of houses and towards the Old Town Square. The Queen herself was in the middle of the turbid flow, her bags hastily packed and then piled atop the roof like those of a gypsy or a tinker. A few minutes earlier she had been wrapped in a furred cape and bundled into the royal coach. Now the brocaded window-curtains did a sad shuffle as the coach teetered along the bridge, its wheels grinding against those of tumbrels and handcarts pulled or pushed by her fleeing subjects. The statues of saints wavered slowly past. They had been decapitated on her orders a few months earlier and now made an eerie sight. Then the wooden statue of the Virgin lurched into view, another wavering ghost. But the driver shouted and showed the whip to his horses. The Queen would cross into the Old Town after all, Holy Mother or not.

Emilia was also crossing into the Old Town. She had fled through the Spanish Rooms with Sir Ambrose, then through the castle; which was empty by then except for a few servants who were trundling hand-barrows piled with furs and casks of wine across the courtyards, claiming what they could before the Imperial troops breached the gates and the looting began in earnest. There would be little enough for them in the library, though. Two of its rooms were ablaze; the flames had filled the corridors with clouds of black smoke and then cast a gaudy, flickering light across the bastion garden and the onion-shaped dome of the cathedral. The cannon-ball had been heated on a brazier and so flames leapt through the wreckage of the wall seconds after it struck. Sir Ambrose had flailed at them with his cape, his enormous shadow vaulting on the wall behind him, but he was beaten back as the flames rose upwards, blackening the plastered ceiling, then the air itself. Spinning round, he had thrust out a black-gloved hand.