Ten minutes later, having followed an ancient retainer in the Pfaffenstein livery of crimson and bottle-green along an immense groin-vaulted corridor and through a series of shrouded and magnificent rooms, they found themselves in the presence of the two old ladies who were now the castle’s sole occupants.

Augustine-Maria, Duchess of Breganzer, was in her eighties, her eagle’s beak of a nose and fierce grey eyes dominating the wrinkled, parchment face. The Duchess wore a black lace dress to the hem of which there adhered a number of cobwebs and what appeared to be a piece of cheese. A cap of priceless and yellowing lace was set on her sparse hair and her rather dirty, arthritic hands rested on a magnificent ivory cane which had belonged to Marie Antoinette.

Her sister-in-law Mathilde, Margravine of Attendorf and Untersweg, was a little younger and in spite of recent shortages, resolutely round-faced and plump. Unlike the Duchess who had received them standing, the Margravine remained seated in order to embrace more efficiently the quivering, shivering form of a goggle-eyed and slightly malodorous pug whose lower extremities were wrapped in a gold-embroidered Medici cope.

Driven back room by room by their poverty, the demands of the war (which had turned Pfaffenstein into a military hospital) and their own increasing age and infirmity, the ladies had taken refuge in the West Tower, in what had been an ante-room connecting the great enfilade of state rooms on the southern facade with the kitchens.

Its round walls were hung with tapestries which Guy suspected had been chosen more for their capacity to exclude draughts than for their artistic content, for they mainly depicted people holding heads: Judith that of Holofernes, Salome of John the Baptist and St Jerome of a dismembered stag. The Meissen-tiled stove was unlit; dust lay on the carved arms of the vast chairs fashioned, it seemed, for the behinds of mountain ogres — but the condescension and graciousness of the ladies was absolute.

‘Welcome to Pfaffenstein, Herr Farne. We trust you found your journey enjoyable.’

Guy, kissing the extended hand and replying suitably, noticed with pleasure that the Duchess spoke what was called ‘Schönbrunner Deutsch’, a dialect which the high nobility shared with the cab drivers of Vienna. And indeed both ladies had been attendant on the Emperor Franz Joseph’s family in the palace of Schönbrunn outside Vienna where the gruelling Spanish ceremonial, the staggering absence of lavatories and the indifferent food had proved an excellent preparation for their present way of life.

Refreshment was offered and refused, the necessary courtesies were exchanged. Then Guy, whose German was fast and fluent, came to the point.

‘You will know already that I would like to buy Burg Pfaffenstein. My solicitors have mentioned the terms?’

The Duchess inclined her head. ‘They are fair,’ she conceded, ‘and we are willing. But as I have already informed your secretary, for a final decision we are awaiting a reply from Putzerl.’

Hearing the name, the pug shot like a squeezed pip from his golden cope and began to run round the room yapping excitedly, causing Guy to exchange an apprehensive glance with his secretary. If Putzerl was the name of the little dog they were in trouble.

The danger passed. For Putzerl, as the ladies now explained, was the great-niece in Vienna, more precisely the Princess of Pfaffenstein and (her mother having been an archduchess) of quite a few other places, and now the sole and legal owner of the castle with its dairies, sawmills, brewery, villages, salt-mine (now defunct) and 56,627 hectares of land.

‘Because, you see, when her father went off to fight he managed to break the entail on the male heir and a great fuss it was. He had to go and see poor cousin Pippi in the end,’ said the Margravine.

‘But we’re certain she’ll agree. She’s been urging us to sell. Putzerl is extremely modern,’ said the Duchess. ‘And of course the money will be invaluable for her dowry because poor Maxi really doesn’t have a kreutzer to bless himself with.’

The dizzying capacity of the Austrians to refer to absolutely everybody by some appalling diminutive or nickname, which Guy had forgotten, now returned to his mind. Having gathered that cousin Pippi was Pope Pius XV, he was now informed, though he had been careful not to ask, that Maxi (alias Maximilian Ferdinand, Prince of Spittau and Neusiedel) was the young man they had picked for Putzerl to marry, there being — owing to the cruel war and the sordid revolutions in various places which had followed it — quite simply no one else.

‘The Gastini-Bernardi boy would have done quite well, actually,’ said the Duchess, on whom the thought of Maxi seemed to be working adversely. ‘But he’s dead. And I must say there always seems to be cholera in Trieste.’

‘Or Schweini,’ said the Margravine, her voice soft. ‘Such a sweet-looking boy.’

‘Don’t be silly, Tilda. The Trautenstaufers only have twelve quarterings.’

‘Still, they’re in the Almanach…’

The argument that followed seemed a little pointless since Schweini, though destined for the Uhlans, had apparently been speared to death by one of his own boars before he could cover himself with glory. Guy, while not wishing to appear indifferent to Putzerl’s matrimonial prospects, now felt free to indicate that he would like to look round the castle.

If he had hoped that he and David would be allowed to roam at will, his hopes were dashed. The retainer was rung for, the pug lowered on to the ground again; shawls, walking sticks and bunches of keys were fetched and the expedition set off.

Within ten minutes Guy realized that Pffaffenstein, inside and out, was exactly what he had been looking for. Its neglect, though spectacular, was recent. In the three months he had set aside for the task he could easily restore it to its former splendour. The huge, baroque state rooms with their breathtaking views over the lake were ideal for his purpose; the guest rooms in the loggia were sound and the outer courtyards with their stables, coachhouses and servants’ quarters would house his workmen without inconveniencing the villagers. Above all, the private theatre with its aquamarine curtains, gilded boxes and ceiling frescoes by Tiepolo was a jewel which would be the perfect setting for the entertainment that was to set the seal on his plans.

But if he had seen enough to satisfy himself almost at once, there was no way of hurrying the ladies.

‘This,’ announced the Duchess unnecessarily as they entered a low building piled from floor to ceiling with skulls, ‘is the charnel house.’

‘Those skulls on the right are from the Black Death,’ said the Margravine helpfully.

‘And the ones on the left are Protestants,’ said the Duchess, murmuring, as she recalled the probable Anglicanism of Guy and his secretary, that there had been a ‘little bit of trouble’ during the Thirty Years War.

But it was before a lone skull displayed on a plinth in a kind of bird-cage and still boasting fragments of a mummified ear, that both ladies stopped with an especial pride.

‘Putzerl found this one when she climbed out through the dungeons on to the south face, the naughty girl.’

‘She believes it’s a Turk and we never had the heart to contradict her, though it is most unlikely. The Turks were all impaled on the eastern wall.’

‘We think it was probably a commercial traveller who came to see her great-grandfather.’

‘About saddle soap,’ put in the Margravine.

‘He came by the front entrance, you see. And poor Rudi was always so impulsive.’

They inspected the chapel with its Eichendorfer altar piece, climbed up yet another massive flight of stairs to the weapons room bristling with flintlock pistols and percussion guns; the museum packed with the heads of wolves, boars and the last auroch in the Forest of Pfaffenstein which Kaiser Wilhelm II had shot, only to be bitten in the leg by the three-year-old Putzerl for his pains… And down again, passing the well into which a seventeenth-century princess of Pfaffenstein, who had not cared for the matrimonial arrangements made on her behalf, had thrown herself on her wedding day.

‘Which was extremely silly of her,’ added the Duchess, ‘because he would have had Modena and Parma had he lived.’

‘Oh, Augustina, but he had no nose,’ expostulated the gentler Margravine. ‘It was all eaten away, you know,’ she explained to Guy, blushing, ‘by a… certain disease.’

‘Putzerl used to sit here on the rim of the well for hours when she was little,’ said the Duchess, ‘waiting for a frog to come.’

‘She wanted to throw it against the wall, like in the fairy tale, and turn it into a prince.’

‘And then one day a frog really did come and she cried and cried and cried.’

‘The frog was so much prettier than a prince, you see — even than Schweini, and he had the most lovely curls!’

‘So she kept it in the oubliette as a pet. Now here,’ continued the Duchess, opening a studded door from which a flight of slime-green steps led down into the darkness, ‘we must be a little careful. But you’ll be interested in the third Count’s collection of torture instruments. It is arranged exactly as the Inquisition left it!’

But at last they were back in the tower room, solicitors’ names exchanged, contracts mentioned and a bottle of Margaux ’83 brought up from the cellar.

‘And how soon would you wish us to leave?’ asked the Duchess, her voice carefully expressionless.

Guy leaned back in his carved chair and, the ladies having given him permission to smoke, selected a Monte Cristo, rolled it between his long fingers and began the careful husbandry that precedes the lighting of a great cigar.

‘There is no need for you to leave at present unless you wish to,’ he said. ‘On the contrary. In fact, you could say that in proposing to purchase Pfaffenstein I am endeavouring to secure your services.’

The ladies, whose small breath of relief had not escaped him, looked at him in puzzlement. ‘What had you in mind, Herr Farne? Not tourists? Because I’m afraid we couldn’t countenance that.’

No, no,’ said Guy soothingly. ‘Nothing like that. I propose to give a house party here at Pfaffenstein. It will last for a week and include a ball, a banquet, possibly a regatta on the lake — and finish with an entertainment here in the theatre. And I want you to select the guests.’

‘Us?’ faltered the Duchess.

Guy inclined his head. ‘I only ask that they should belong to your social circle.’

‘You wish to entertain our friends to a banquet and a ball?’ said the stunned Margravine.

‘And a house party to follow,’ repeated Guy. ‘I myself shall bring only one guest: a lady.’

Guy’s voice had been carefully expressionless but David leaned forward, aware that he had touched the heart of the mystery. At the same time he felt an inexplicable sense of unease.

‘A lady to whom I hope to be married,’ Guy continued. And answering David’s look of bewilderment, the slight hurt in the boy’s face, he added, ‘She is the widow of an officer wounded in the war and her period of mourning will only end in June, so no formal engagement exists as yet.’ He paused, and David saw the extraordinary change in the colour of his eyes as he remembered happiness. ‘I knew her years ago in Vienna.’

‘She is Austrian?’ enquired the Duchess.

‘No, English, but she loves your country. I should add perhaps that I am myself a foundling and was discovered in circumstances so disreputable that they must entirely preclude my seeking an entrée into the nobility. Indeed, my ambitions in that direction are non-existent. It is otherwise, however, with Mrs Hurlingham. Her aunt,’ said Guy, who had been made well aware of the fact, ‘was an Honourable.’

The ladies exchanged glances. ‘That is not a very high rank, Herr Farne,’ said the Duchess reprovingly.

‘Nevertheless she wishes, most understandably, to take her place in society. And I,’ he went on, his voice suddenly harsh, ‘do not wish her to suffer from being married to a man who is not even low-born but not “born” at all.’

‘It will be difficult,’ stated the Duchess.

‘She is not perhaps a Howard? Or a Percy — the aunt?’ enquired the Margravine hopefully.

‘I don’t think so.’

‘Oh, dear.’ The Duchess was perplexed. Well versed in the ways of the world, she was aware that the attractive Herr Farne with his wealth and obvious indifference to what anybody thought of him would be accepted far more easily than a fiancée with aspirations. ‘You see, our friends are rather particular. Prince Monteforelli, for example…’