Emilia knew nothing about the Corpus hermeticum. The name reminded her, though, of some of the books she stumbled across in the castle in Breslau on the night of the feast, those whose titles suggested impious pursuits. But Vilém swore there was nothing impious about the Hermetic texts. Indeed, parts of them were even thought to foretell the coming of Christ. Together they consisted, he explained, of some two dozen books, along with who knew how many others that had disappeared over the centuries following other invasions, other wars. Some of the books dealt with philosophical subjects, others with theology, still others-the ones that attracted the most readers and commentators-with the arts of alchemy and astrology.

None of this made the least bit of sense to Emilia. How could a manuscript of fourteen pages-a few scraps of goatskin scribbled with a mixture of lampblack and vegetable gum-possibly be valuable enough for someone to kill for?

Vilém was still talking as the boat wound its way along the edge of the Hornchurch Marshes, twisting and then righting itself in the currents that eddied dangerously at each bend. His words tumbled out of him so quickly she could barely follow them. The Corpus hermeticum described a whole universe, he said, a magical place whose every part, from the moons of Jupiter to the smallest mote of dust, formed the threads of an ever-radiating web in which each atom was connected to every other atom. The parts also attracted and otherwise influenced one another so that a subtle but intimate connection existed between, say, the flow of the blood in the body and the flight of the stars through the heavens. These amazing influences could be detected by means of secret signs inscribed across the surface or in the core of every living thing and, once detected, could be manipulated and exploited so that wounds would be healed, diseases cured, events foretold or forestalled-the destinies of entire kingdoms interpreted or even changed. The man able to read these bristling hieroglyphics, these secret scriptures, was therefore a magician possessed of stupendous powers, capable of turning the influences of the heavens to his own ends. And any book purporting to describe these secret marks, to catalogue and explain them… well, the value of any such volume would be past measure.

'So the parchment is a magical book of some sort?' she managed to interrupt at last. 'And that is why Prince Charles wants it?'

'So it would seem, yes. No doubt he wants it to ornament his library in St. James's Palace. But perhaps there is another reason as well.' Vilém raised his eyes from the casket. 'For the manuscript now possesses political as well as magical powers.'

The place of the Corpus hermeticum in the pantheon of literature was now more complex, he explained. Rome had grown suspicious of the Hermetic texts. Some of the books may well have predicted the coming of Christ, if interpreted in a charitable light by the Vatican's consultors. But other Hermetic teachings were a threat to orthodoxy. Of special concern were those passages on the structure of the universe and the divinity of the sun. After all, Copernicus himself had quoted from the Asclepius at the outset of De revolutionibus orbium coelestium, the heretical volume that dethroned the earth in favour of the sun. But even worse were the political dangers now coming from those who fingered the pages of the Hermetic texts, which were currently appearing in dozens of new editions and translations. Philosophers like Bruno and Duplessis-Mornay had dreamed of ending the wars of religion between Catholics and Protestants by promoting the philosophy of Hermeticism as a substitute for Christianity. But to the authorities in Rome the Hermeticists were, like the Jews, supporters of the Protestant cause who wished to erode the powers of the Pope. The suspicion was not without foundation. By the year 1600, when Bruno was martyred, the books had become the lodestone for all manner of heretics and reformers. Dozens of sects and secret societies began burgeoning all over Europe, like mushrooms in nightsoil: occultists and revolutionaries, Navarrists and Rosicrucians, Cabalists and magicians, liberals, mystics, fanatics and false Messiahs of every hue, all demanding spiritual reform and prophesying the downfall of Rome, all quoting the ancient writings of Hermes Trismegistus as their authority for a universal reformation.

'The Counter-Reformation is losing its footing,' Vilém explained, 'despite the armies of Maximilian and the bonfires of the Inquisition. A Pandora's box has been opened which Rome is trying to slam shut by whatever means. Sorcery and magic now rank with dogmatic heresy. Cabalist literature has been put on the Index and in 1592 Francesco Patrizzi, one of the translators of the Corpus hermeticum, was condemned by the Inquisition. The Jesuits at the Collegio Romano have begun an Index of their own, a list on which the works of Paracelsus and Cornelius Agrippa have been placed alongside those of Galileo. Johann Valentin Andreae, founder of the Rosicrucians, has been pronounced a heretic by the Cardinals of the Inquisition. Traiano Boccalini, Andreae's mentor, a supporter of Henry of Navarre, was murdered in Venice, while Navarre himself, the polestar of all of these hopes, was assassinated in Paris. But the movement is Hydra-headed and unstoppable. With Navarre's death came a new hope, a new axle round which everything else could gather and spin.'

'The Elector Palatine,' murmured Emilia. 'King Frederick.'

'Yes.' He gave another shrug. 'Another hope that proved a sad delusion.'

A few lights along the shoreline wavered slowly past. The barge had shunted into Gallion's Reach, avoiding the landing piers that projected into the ink-black water. The boat's wake as it passed stirred to life the strings of moored lighters whose hulls bobbed in the swell. Beyond the jetties and mud banks lay nameless hamlets and tumbledown cottages. They had been in the barge for over two hours now, but the river had narrowed only slightly. At times the shore seemed to vanish.

'So the parchment is a danger to orthodoxy.' She was beginning to understand the stakes involved, or thought she did. 'Rome hopes to suppress it, to stamp out its heresies before they can take hold.'

'Very possibly. At the moment Rome is terrified of any threat to its dogma, of a split that would undermine its fight against Protestantism. Galileo with his moons was one such threat, but four years ago he was silenced by the Holy Office, warned by Cardinal Bellarmine not to write another word in defence of the heretic Copernicus. The appearance of another document in support of Copernicanism or any other heresy would, however, be a drastic blow, especially at this time.'

'And especially if it came from an authority as great as Hermes Trismegistus.'

'Yes. So the manuscript will be locked away in the secret archives of the Bibliotheca Vaticana if the cardinals and bishops lay their hands on it. Perhaps it will even be destroyed.' Once more he lowered his gaze to the cabinet between his feet. 'Except there is something else,' he said slowly, 'something I fail to understand. For in the past few years the authority of Hermes Trismegistus has been challenged, even destroyed. Not by the theologians of Rome, but by a Protestant, a Huguenot.'

There had been a recent dispute, he said, between a Protestant scholar, Isaac Casaubon, and a Roman Catholic, Cardinal Baronius, Keeper of the Vatican Library-the man who, Vilém claimed, now wished to cart off to Rome both the Bibliotheca Palatina and the manuscripts in the Spanish Rooms. Years ago the Cardinal had published a massive study about the history of the Church, the Annales ecclesiastici, in which Hermes Trismegistus was described as one of the Gentile prophets along with Hydaspes and the Sibylline oracles. This treatise was much admired by Vilém's teachers, the Jesuits in the Clementinum, but since then it had been soundly refuted by Casaubon, a Switzer, a Huguenot who had come to England at the invitation of King James. And Casaubon's magnum opus, De rebus sacris et ecclesiasticis exercitationes XVI, published six years earlier in 1614, was said to prove beyond doubt that the whole of the Corpus hermeticum was a forgery composed not by some ancient Egyptian priest at Hermoupolis Magna but instead by a band of Greeks living in Alexandria in the century after Christ. These men had cobbled together a mishmash of Plato, the Gospels, the Jewish Cabala, together with a few scraps of Egyptian philosophy, and had managed to hoodwink scholars, priests and kings for more than a thousand years.