My hammering on the door of the rector's lodgings was so frantic as to bring the servant running to open it with an expression of expectant dread, as if he feared news of another tragedy.

"I must speak with the rector immediately," I gasped, brandishing my papers in his face.

"He dines at Christ Church tonight, sir, with all the senior men." He regarded me anxiously, his hand trembling slightly as he held up a candle to see my face, sending shadows skittering up the walls. "Has something happened?"

Of course-I had forgotten how early it still was; Underhill would be celebrating his triumph this evening and may not return for some hours yet.

"It is a matter of great urgency," I said, trying to catch my breath. "I can wait for him, but I must speak to him tonight."

The servant, a severe man perhaps in his late fifties, eyed me with some suspicion.

"You may call back at a later hour, sir, but it would not be proper for me to allow you to wait in the rector's lodgings with the ladies here alone."

"I intend them no harm-I wish only to be sure not to miss him."

"Who is it, Adam?" called Sophia's voice within, and then she appeared behind the servant, her slender figure illuminated by the candles, a book in her hand.

"'Tis the foreign gentleman, Mistress Sophia, come to see your father. I have told him to call again later."

"Nonsense-let him wait in the warm, I am sure Father will not stay out long. Conviviality is not his strong suit," she said, smiling to me over the servant's shoulder. "Doctor Bruno, good evening-please do come in."

The servant glanced from me to her with consternation.

"I do not think your father would approve, Mistress-" he began, but Sophia waved a hand to interrupt.

"Doctor Bruno is my father's guest, Adam, and a philosopher of most prestigious reputation-I'm sure Father would be appalled if I did not extend to him the proper hospitality. Perhaps you would be kind enough to take Doctor Bruno's cloak and fetch some wine?"

Adam seemed extremely put out, but allowed himself to be commanded, bowing curtly to me and standing aside to let me enter with a further look of distaste. Sophia smiled again, and gestured for me to follow her through the high dining room we had occupied the previous evening to a door on the other side. She was wearing a plain green gown and her dark hair fell in ripples down her back as she walked, with the kind of self-possession that comes from natural beauty. My spirits greatly cheered by the unexpected prospect of her company, I followed her into a dark-panelled room, warmed by a low fire and dominated by a great oak desk under the window, piled high with books and papers.

"This is my father's study-you may wait for him here," she said politely, ushering me to one of the tapestried chairs that bordered the hearth. She watched me for a moment. "You did not wish to celebrate with the Fellows at Christ Church this evening then, Bruno?"

"I was not in the mood for a feast. I'm afraid to say your father carried the audience with him tonight." I eased into my seat and leaned nearer to the twisting flames. "In that, at least, he may consider himself the victor."

"Did he ride roughshod over your every point without taking the trouble to actually listen?" she asked, smiling with a bitter sympathy. "My father has no skill in debate, Bruno," she went on, without waiting for me to respond, "he has only the unshakable conviction of his own rightness, yet it is surprising how effective that can be in rebutting argument. I used to think it was a mark of arrogance, but as I grow older I begin to suspect it may be fear."

I raised a questioning eyebrow, thinking how perceptive she was for such a young woman.

"He has been so dependent all his life on the favour of great men like the Earl of Leicester, as academics and clergymen are," she continued, a note of pity in her voice, "and he knows well how capricious such preferment can be. So he lives in constant fear of losing his position-and there have been so many factions in the university these past few years, so many people denounced for being seen in the wrong company, reading the wrong books, making a chance remark that could be maliciously interpreted." She sighed. "Poor Edmund Allen's fall shook him badly."

"Why-does he secretly favour Rome too?"

"Oh no! God, no, he is the last person-" She shook her head fiercely, as if to underline how preposterous the idea was. "But to see how the Fellows rushed to close ranks against Allen, against all ties of friendship, in case they should be tainted by association. An accusation need not be true to stick, you know, in these times. My father craves stability more than anything, and believes that change is always for the worse. He is not a bad man, but he is constantly glancing over his shoulder, and that makes him defend his certainties like a mother bear defends her cubs. This, I think, is why he appears so pompous."

She grinned, and leaned forward to poke the fire. There was a soft knock on the door and the servant Adam came in with a pitcher of wine and two cups, which he set on a low wooden footstool near the fire.

"Thank you, Adam. Would you send to the kitchens for some bread and cheese and any cold pie they might have? I suspect our guest may be hungry."

I nodded my grateful agreement, only now realising that my affronted withdrawal from the dinner at Christ Church meant that I had missed supper, and my stomach was beginning to complain.

Adam bowed, shot me another look to signify his disapproval, and pointedly left the door open when he went out. Sophia rose to close it, brushing down her dress. I poured us both a cup of wine.

"You were banging on the door fit to wake the dead there, Bruno," she said, settling herself again in the chair opposite, tucking her feet neatly under her like a cat, "and your face was pale as the grave-I feared you brought us news of more horror."

"Nothing so terrible, I assure you," I said, taking a long drink.

"Then what brings you here with such urgency? Have you thought of some brilliant riposte that you forgot to make during the disputation and brought it round so my father can hear it late rather than never?" She smiled mischievously, indicating the paper I still clutched.

"No-that will come to me during the night," I said, only half joking, as I passed it to her. "What do you make of this?"

She skimmed her eyes briefly over it and looked up at me, puzzled.

"But this is a map of the heavens according to your Copernicus, is it not?"

I nodded.

"But why bring it to him now in such haste, after the debate is over?"

"Nothing strikes you as odd about it?"

She frowned at the paper again, and then her eyes widened, just for a moment, before she raised her head again. "That is a strange way to represent the sun," she said lightly.

"Yes."

"Like a wheel. But it is very elegantly drawn," she added, handing the paper back.

"It is, but I cannot claim the credit for that-it is not my work."

"Then…whose?" Her voice faltered for a moment. "Where did you get it?"

"It was sent to me. By who, I don't know, but it may have a hidden meaning. I thought I would ask your father's advice."

A strange laugh tumbled from her, as if in relief. "You came haring round here, pounding on the door as if the world were ending, just to show him this? If you would take my advice, Bruno, I would guess that someone is playing a joke at your expense, making fun of Copernicus. My father may not like you wasting his time with such trifles."

"Perhaps you are right," I said neutrally, folding the paper and smoothing it between my hands. "All the same, I will wait for him, if I may?"

She nodded briefly. What, I wondered, was the expression that had flitted so briefly across her face a moment ago when she looked a second time at the diagram? Had it been recognition, or even fear? It seemed improbable that she could know anything of the hidden meaning of the little symbol but then, I reflected, the life of the college was so close-knit that perhaps there were no secrets here. If the symbol meant something to Roger Mercer and to my unknown correspondent, why should it not be known to others, Sophia among them?