He put his fingertips together and I braced for a lecture.

T he means were obvious from the start,” the Maestro said. “Even before he left this house I knew that the procurator had ingested poison. I knew the name of that poison. There is no known antidote. Any physic other than time and rest would have been hazardous in a man of his age, so I recommended none. I knew from its effects that the drug had almost certainly been administered in this room, and madonna Bianca later confirmed to my apprentice that her grandfather had eaten nothing for some time beforehand.

“Most crimes have an obvious motive, but this one did not. The procurator had reached the pinnacle of his political career, his honored son now supervised the family business affairs, and most of his old enemies have long since preceded him to a better realm. The minister will understand that I speak in generalities when I note that family members are generally more likely to have motives for violence than strangers are, unless we include footpads and pirates, who are not in evidence in this case. I trust that Ambassador Tirali will take no offense at an observation that poison seems an extreme way to eliminate a rival bidder in a book sale.”

Vasco was whispering a translation to the Feathers. The Maestro paused to let him catch up.

“I am happy to learn,” Ambassador Tirali remarked, in a heavy-handed parody of the Maestro’s style, “that my notoriously voracious acquisitive bibliophilic instincts are not suspected of leading me into mortal sin. As I told sier Alfeo yesterday, a political motive seems equally improbable. So why was Bertucci murdered?”

The Maestro was not about to spoil his own enjoyment by telling him that, not yet. “I could see no ready answer. Sir Bellamy and his wife are strangers, visiting our city to buy art, not to murder our national heroes. Our host here and the servants seem equally improbable killers. I was forced to wonder if the intended victim could have been someone else, such as our Most Serene Doge Pietro Moro. When the book dealer Karagounis was exposed as a Turkish agent, this explanation suddenly became worthy of serious consideration. The doge testified to Alfeo that he chose to drink retsina, which he rarely touches, simply because he knew the procurator would be here and would choose it. So an accidental switch of glasses must be considered.

“But consider the complications required! The doge should not have left the palace without his counselors. He should not have consorted with foreigners. He did so, he told Alfeo, because at the last minute he received a note from his old friend warning him that the books actually sold might not be those he had been shown.”

“I object!” The howl came from Ottone Imer.

Nostradamus dismissed his complaint with a wave of his hand. “I do not say that was the case, attorney. I merely report what the doge said, quoting a note from the deceased, who might, just possibly, have been deceived by a deliberately planted rumor. Or the note might have been forged. But the chances that this too-complicated trap would lure the doge here in person were extremely remote, and even if he did decide to come and see for himself, why go through all the legerdemain with poison and retsina-a wine the doge was very unlikely to choose anyway, so far as a man like Karagounis could know?”

“I told him,” Imer grumbled. “I told him no one would want it, but he insisted on bringing some.”

“Quite. As I was saying, to a Turkish agent the poison would be an unnecessary complication. An ambush in a dark doorway would be far more effective. So you see, Your Excellency-” now the Maestro carefully addressed the inquisitor “-although the official theory cannot be absolutely disproved, it requires a lot of unlikely suppositions. Pluralitas non est ponenda sine neccesitate, ^ 1 as the saintly Brother William of Ockham taught us.”

Dona did not comment. He did not look very pleased, either, from what I could see of his face from where I was sitting. I glanced at Violetta, and she was smiling quietly at no one in particular. So she had seen the answer! I wondered whether she had applied Aspasia’s sensitivity or Minerva’s logic.

Having trashed the official government verdict, the Maestro pressed on. “ Vizio, ask Sir Bellamy for me: When he and his lady visited Karagounis at his residence to view whatever books he had for sale, did he offer them wine?”

Translation…Bellamy nodded.

“Retsina?”

Hyacinth pulled a face and said what Vasco translated as, “The madonna says that whatever it was it tasted terrible.”

“You see,” the Maestro continued happily, “we assume that the poison could not have been concealed in the other wines-although this is not certain, because no authority I have consulted gives a recipe for isolating venom from the leaves and I have not had time to carry out my own experiments. But very few people have a taste for retsina. So the question becomes, who else was drinking retsina that night?”

“I tried it,” Pasqual said. “But I promise never to do so again. And while I have the floor, I will point out that I never stood next to Procurator Orseolo. There was always at least one person between him and me.”

“Oh, this is a stupid waste of time!” Minister Orseolo made as if to rise. “If you have an accusation to make, then make it now. Otherwise my children and I are leaving.”

“Two minutes more, if you please, Your Excellency. I think some of you know whom I am about to accuse?”

Violetta said, “Yes.”

Orseolo sat back again, glaring at her. Just about everyone else was frowning, except Bianca and Benedetto, who both looked horrified. There was a murderer in the room?

“Very well,” the Maestro said. “One more digression and I am done. The poison in question is not available for purchase in the city. Sier Alfeo established this for me the next day. That means that the murderer obtained it from the mainland or from even farther afield and the crime was planned long in advance. Unfortunately, this information is not as useful as one would like. Madonna Bianca, for example, would seem to have no opportunity to acquire the herb in question, even if some demented nun in the convent had taught her its properties. But her brother attends university in Padua. I assume he came home for Christmas and…No, I am not suggesting that the procurator’s grandchildren conspired to murder him! I am just pointing out that the poison could have been acquired, given time, by almost anyone in this room. It tells us only that the motive was not a sudden impulse. Either the murderer planned the crime well in advance…” He paused, enjoying the attention like a child performing for family friends.

“Or?” Minister Orseolo demanded.

“Or the murderer is a professional killer, Excellency.” The Maestro stretched his lips in a smile. “Madonna Bianca, are you certain that no one put poison in your grandfather’s glass?”

She was by far the youngest person in the room, reared in the shelter of the cloister, but she held her chin high and was not intimidated. “I did not say that, Doctor Nostradamus! I said I did not see it happen. But I was keeping an eye on his drink, in case he forgot it. I should have seen if anyone had tampered with it.”

“Except once. You noticed the doge leaving, because he walked out when the attorney and Sir Bellamy were having their shouting match. They made so much noise that a servant looked in to see what was going on. That was the only moment when everyone was distracted and the substitution would have been safe.”

I watched faces, as many as I could. I saw realization and even some nods. Imer was twitching again.

“So who,” the Maestro said, “would have known that there would be a convenient ruckus? Who could have obtained the poison somewhere outside the city and had it ready to tip into a glass or switch glasses? Not Feather himself. All eyes were on him. But his wife fits these requirements.”