“But the Feathers had no known motive and she had used a very potent and obscure toxin, not some crude rat poison. The logical conclusion was that they were hired killers, acting for someone else. In which case the true murderer was not there that night! ”

That took him longer, but Bianca understood, and her eyes were wide with horror.

“In other words,” I said, “the rest of the people present were innocent. Who was not present who had a motive?” A lurid imagination might have considered blaming the Council of Ten or even the papacy, which has had a reputation for using poison ever since the days of the Borgias. I did not bother going up those blind calli.

“I never asked your father where he had been that evening, and I am sure his duties as great minister could have been arranged to provide him with an excellent alibi, had he known that he would need one. Besides, if he had wanted to kill your grandfather, he would have taken much less risk by administering the poison himself, at home. But you, sier Benedetto, were not only in Padua, miles away, you were in jail that night. Your alibi, clarissimo, was much too good! It could have been arranged very easily, though, at the cost of a dribble of blood and a little pain. You at once became the obvious suspect.”

He blinked owlishly.

His sister said, “That’s absurd! He wasn’t in the city. Why did he need any better defense than that?”

“Because he did not know how the killers he had hired were going to strike. He knew the likely day, but not the means they would choose. He probably expected sier Bellamy to jump out of the shadows and attack the old man with a sword. A fast boat down the Brenta can bring a man from Padua to the lagoon of Venice in a couple of hours. He could kill a man here and be home in Padua by morning. So clever sier Benedetto arranged to spend the night in a Paduan jail, well out of suspicion’s way. I expect he set up an immovable alibi every time the procurator was due to leave the Procuratie.

“When I worked that out, I was convinced, but such logic would not stand up in court. Having demonstrated that your father had tried to kill me, the Maestro accused him of the murder that did succeed. No doubt he expected the Three to take over the case at that point and discover the real truth by interrogating the Feathers. But your father accepted the blame for both crimes. Obviously his confession was a lie and he was sheltering one of you, his children. Possibly both of you, but if you had wanted to kill the old man, madonna, you could have done so at any time. You could have stumbled on the stairs and tripped him.”

Her eyes flashed. “I wish now that I had!”

So did I. “But you didn’t. That left your brother.”

“Why do you say my father’s confession was an obvious lie?”

“Because it was ridiculous. A great minister certainly knows all about the Council of Ten, and the Council of Ten most certainly keeps its unwinking gaze on ministers. He could never have hoped to have an affair with a foreigner and keep it secret. Never! At best he would be stripped of his office and sent into exile. At worst he would die as a traitor. I don’t suppose he ever set eyes on Hyacinth Feather before tonight.”

I also had great difficulty imagining Enrico Orseolo losing his head over a woman like Hyacinth Feather, but love is blind and my opinions were not evidence. No matter-by elimination, the mastermind had been the drunken sot on the rug at our feet.

“It was me,” he said quietly, staring at the fire. “I found the foreigners in jail in Padua, charged with conspiring to murder a rich old woman. I paid for their defense by selling some jewels our mother left me last year. She did not leave them to Bianca, because Bianca was destined for the convent. I got the foreigners off and promised them more money if our grandsire died before Easter. I told them all about him, everything I could think of.”

I had guessed that. “Even his taste in wine?”

He nodded. “But he almost never went out. Not even to the Senate any more, just to sales of books or paintings. I suggested they pose as buyers to meet him. Bianca knew nothing about the Feathers, I swear!”

“But I kept writing you helpful letters,” Bianca said bitterly. “Day after day. I told you about every chance I got to go out, every trip to the market or the book dealers. I told you everything that was planned. I had nothing better to do than write you letters and dream of the next time Grandsire would take me to an art auction. That’s how that awful woman knew everything, messer -I told Bene and he told her.”

“When did your father find out?” I asked.

For a while Benedetto continued to stare into the fire as if he had not heard me. Then he muttered, “The night you went to the Feathers and started asking questions…You scared them. Bellamy came to see me and told me I must pay them right away so they could leave Venice. I had no money with me. I went and wakened Father. I confessed. He knocked me down, he was so furious. I got up and he knocked me down again. He said he would have heard by then if the Ten suspected murder, but he said we must stop Nostradamus. The old man was too clever, he said. If we could just remove you, then the man would be helpless and we would be safe. He paid Feather something to get rid of him. Then he and I went out together, to see some men he knew. It was not an area for a man to go alone.”

“But why kill old Bertucci anyway?” I asked. “Just because he was getting old and cranky?”

Benedetto turned to look at me for the first time. His eyes were still bleary but a sudden rage seemed to sober him. “Not for me. For Bianca. Because he was a tyrant! A despot. I could put up with him jerking my strings for a year or two more. But if he forced her into taking her vows, that was a life sentence! You know what they would do to her? She has to lie on the floor and be covered with a black cloth, while they sing and pray over her-three times they do that. And they take away anything pretty like embroidery. And then they cut off her hair, while the whole congregation watches. Every nun in the convent comes and cuts off a lock of her hair and throws it on the ground. Snip, snip, snip…They wrap her in sackcloth and put a crown of thorns on her head…” Bene began to weep. “And it’s forever! She’s locked up until she dies. Do you wonder she was terrified? The old man was crazy. He should have been locked up, not her. Father would never stand up to him, no matter how bad he got.”

So it was all his sister’s fault? What pathetic trash he was! He could not even kill himself properly. Bianca was sobbing too, silent tears flowing down her cheeks. In her place, I would have taken up the fire irons and made a clean sweep of the Orseolo males.

And that was the unthinkable love of the quatrain. I am certain that there was nothing carnal about it, just brotherly love carried to the point of madness.

It was time to go, or I would fall asleep in my chair. “Your father is trying to save you. He can only die once, so he took all the blame. I knew he was lying. The Maestro knew he was lying, and Inquisitor Dona knew he was lying-but he accepted the confession. You’ve got your life back, Benedetto Orseolo. Try to put the rest of it to better use.”

“You mean that?” Bianca whispered. “The Three won’t send Missier Grande to arrest him?”

“I don’t think so. Dona will have to talk the other two inquisitors into it, but I think they will go along.” The Lizard would make his last deal.

“You’re wrong,” the boy said. “They won’t hang father for trying to kill you. The Ten will take his money instead.”

Bianca stared at me, waiting for my comments. This was the crux of the problem. Shamefully, there are precedents. More than one noblemen convicted of murder has offered to pay an enormous fine instead and the Council of Ten has accepted it.