What was his plan? With nothing to read on the journey and little to see through the quarter-lights except expanses of rock and snow, she had had hours to puzzle over the parchment in the library and the three horsemen, even about the imponderable Sir Ambrose himself. Various plots had begun to suggest themselves. Throughout the spring and summer, she knew, dozens of strangers had arrived in Prague Castle. These were not the usual students and scholars, those humble pilgrims who travelled on mail-coaches or mangy mules. No, these had been visitors of a different sort, often liveried or else bearing sealed letters of introduction from dukes and bishops in every corner of the Empire, and from France, Spain and Italy as well. 'Turkey-buzzards', Vilém had called them. Rumours were abuzz, he explained, that in order to finance his armies King Frederick was preparing to sell the treasures of the Spanish Rooms-hundreds of paintings, clocks, cabinets, even the telescopes and astrolabes made by Galileo himself. A 500-page catalogue had been drawn up in secret by the Bohemian nobility and then distributed among the potentates of Europe. Their agents arrived in Prague Castle soon afterwards, one step ahead of their marauding armies.

Of course, a good many books from the library had been included in the enormous catalogue. Frederick was planning to sell them like a costermonger hawking cabbages in the street, Vilém bitterly complained. And naturally there were as many buyers for the books as for everything else, especially for the most valuable ones, including the Golden Books from Constantinople. In Rome, Cardinal Baronius-the man who oversaw the gargantuan task of cataloguing the Vatican Library-was said to have interested the Pope in the collection. It must have been a difficult task, Vilém sneered, for Paul V was a vulgar man, a detestable philistine-the same man who had censored Galileo in 1616 and placed the work of Copernicus on the Index. But apparently His Holiness was now interested in acquiring not only the treasures of Prague but also Frederick's patrimony, the books in the Bibliotheca Palatina-the finest collection of Protestant learning in the world.

And now it seemed that the books in the library had brought someone else to Prague, another agent who was equally mysterious. She shivered in the chill, watching as Sir Ambrose supervised the soldiers, who were now carrying a succession of crates and portmanteaux indoors for the night. The Queen's baggage had already been unloaded and the horses stabled. The remains of the convoy twisted around the square and into a dark side-street, where the oxen were coughing and lowing or else sticking their broad heads into nosebags. The soldiers wove their way among the vehicles, working silently and swiftly, until one of them, struggling to raise a crate from a wagon, stumbled in the snow. The crate tumbled to the ground with the sound of breaking glass.

'Oaf!'

Sir Ambrose struck the prone soldier sharply across the posteriors with the riding-stick, then drew his scimitar and violently prised the lid from the damaged crate. Emilia, still at the window, leaned forward. The crate appeared to be packed with straw and filled, not with books, like so many of the others, but, rather, with dozens of flasks and bottles, several of which had broken and were spilling their contents across the snow. Whatever the liquid, its stench must have been powerful, for the soldiers quickly retreated several steps, gagging and covering their noses. But Sir Ambrose knelt in the snow and carefully inspected the bottles before resealing the lid with a few blows of a mallet.

Emilia was puzzled by the sight. At first she thought the bottles must have come from the royal wine cellar: had Otakar not claimed that Frederick was shipping his wine collection from Prague along with everything else? But the bottles were too small; they looked more like flasks or vials. She decided they must have come instead from one of the castle's numerous laboratories. Prague Castle was honeycombed with such mysterious places; no one lived in Prague for a year without hearing tales about them. The Emperor Rudolf's dozens of alchemists and occultists had practised their secret arts, it was said, in special rooms tucked away in the Mathematics Tower. The library was crammed not only with their published works, Vilém once told her-with copies of Croll's Basilica chymica, Sendivogius's Novum lumen chymicum and Thurneysser's Magna alchemia-but also with their manuscripts, hundreds of documents inscribed in bizarre codes composed of astrological signs and other chicken-scratchings. She wondered if Sir Ambrose was transporting these dubious masterpieces across the snowy wastes along with the powders and potions from their hidden laboratories? Some strange business was afoot, of that she was certain. Perhaps Sir Ambrose had been, on top of all else, an alchemist, yet another of Rudolf's superstitious wizards?

She drew back the moth-eaten curtain a few more inches, pressed her brow against the frosted pane and searched for a last glimpse of Sir Ambrose. But he had already vanished into the darkness with the wooden crate clutched in his arms.

Chapter Three

Eight o'clock. Morning came seeping across London in pale-pink and pearl-grey veins of light. The city had been up for hours already: seething, clattering, belching, chiming, singing, sighing. But a darkness lingered in the sky despite the season. Gnarled strands of smoke rose upwards to filter and tease apart the morning light, like dozens of genies released from flanched bottles scattered from Smithfield to Ratcliff and for as far along the estuary as the eye could see. They returned to settle over the city in a fine black powder, tarnishing, coating and corroding, a steady dredging from which there was no escape. The gammons of bacon hanging in Leadenhall Market were already rimed with black, as was every collar, hat brim, awning and window-sill the city over. And matters would only get worse, because even at this early hour came the promise of heat, and with the heat would come the smell. Beside the Thames the stink of the silt mixed with the sweeter exhalations of the molasses, sugar and rum in the jumble of decrepit storehouses and manufactories that pressed up from the quays, together with the acrid tangs of the sea-wrack and snails exposed by the ebbing tide. The wind came from the east, unusual for that time of year, and guided the foul-smelling cloud upriver, through the endless reticulations of brick streets, sunless courts and alleys, half-opened doorways and windows, into the city's every fold or recess.

The stench was already catching in my throat and stinging my lungs as I crossed under the north gate of London Bridge and headed into Fish Street Hill. From Nonsuch House it would take me some twenty minutes to reach Little Britain, which was to be the first of my stops this morning. From there I would walk south into St. Paul's Churchyard and Paternoster Row. Then, if I still had not found what I sought, I would catch a hackney-coach to Westminster. Not that I really had expectations of finding anything in the clutter of second-hand bookstalls outside Westminster Hall, or even in the bookshops of St. Paul's Churchyard or Little Britain for that matter. As I limped forward on my thorn-stick I was frowning into my collar, which I had drawn up over my nose in an unsuccessful attempt to keep out the foul stink. It promised to be a long day.

I had decided over breakfast an hour earlier that it was time to begin my search for Sir Ambrose's parchment. But now, even before I was halfway up Fish Street Hill, I regretted my earlier resolve. Not only were the streets crowded and foul-smelling, but yesterday a search of my shelves and catalogues for editions and copies of the Corpus hermeticum had failed to turn up a single reference to The Labyrinth of the World. Yes, a long day. I ducked my head and hurried past a throng of people gathered to watch a cart-horse wallowing on its back in the middle of the street, hoofs wildly flailing.