"Not precisely a school," Laius said. "I do not teach children. My efforts are directed towards those adults who would improve their Latin, their deportment, and their rhetorical skills to enable them to better fit in with their, ah, new-found place in society."

"Ah, I see," Quintilian said, and he did smile. "You teach the newly rich to, as some would put it, ape their betters."

"Some might put it that way," Laius said defensively. "It is true that my students are, for the most part, freedmen and former slaves who have succeeded in making their fortunes in trade, or other occupations frowned upon by the patrician landowners. But some of those same landowners . . . well, never mind; I'm sure you don't want to hear my protests about the social order."

"Perhaps some other time," Quintilian said. "Right now I'm more interested in ghosts."

"Yes, of course. That's why I'm here." Laius hitched up his toga and sat down. "I 'saw this supposed ghost, it would be, four days ago. Here in the palace."

"Just when and where, if you can remember."

"Remember? How could I forget? I was waiting in a courtyard - I'm not sure just which courtyard, there are so many of them in this place, but I could find it again if you like - when this person appeared in the middle of a tree about twelve feet off the ground."

"A tree?" I exclaimed.

They both looked at me. "It turns out that it was a potted tree," Laius explained, "and the pot had been moved so that it concealed a balcony. The person was on this balcony. 'Vespasian; he said, 'Vespasian, beware the Ides of October! Mind what I say!' And then he screeched, and stepped backwards until he was out of sight."

"Your description," Quintilian said, "makes it sound as though you do not believe the person was a ghost. Is this so?"

The teacher of oratory thought for a moment and then nodded. "I am being cautious about calling it a ghost, because I do not think it was a ghost," he admitted. "Although the three or four other people in the courtyard at the time seemed to have no such doubts. They trembled and fell on their knees, and one of them went screaming out the entrance. But for me, I saw nothing ghostly about the figure. True, it did resemble Gaius Julius Caesar, but my uncle Timidus bears an uncanny resemblance to the god Bacchus, as may be seen by comparing him to many a mural in the various houses of joy about the city."

"I see."

"And besides, the person spoke with the slight hint of a foreign accent."

"Really? You are the first to note that."

"Most people wouldn't. You see, the problem was that his Latin was a hair too perfect, as though it had been learned as an adult. Much like some of the people I teach."

"So you couldn't say what sort of accent?"

Laius shook his head. "From the East, rather than the North, I would say; but aside from that, no."

Quintilian nodded. "Thank you, citizen Laius. One last question: What were you doing in that courtyard?"

"Waiting to see the imperial procurator. My father's estates were confiscated by Nero, and I am engaged in a continuing struggle to get them back."

"With what luck?"

"None - absolutely none. It matters not that most of the policies of Nero have been rescinded. In matters of property, the government is most reluctant to retrace its steps. I suppose they're afraid to open the box. I mean, if an estate grabbed by Nero is returned, then what about one confiscated by Claudius, or even Augustus?"

"There is something in what you say. But, if it is so hopeless, then why do you keep trying?"

"It gives me an air of moral authority among my patrons. Knowing that there's a chance, however small, that I may one day once again be as rich as they are causes them to treat me with ever-so-slightly more respect than they would otherwise."

"Thank you again, citizen Laius."

"Have I been of some help?"

"You have added to our store of information, and that is always helpful."

Our next guest was a senator, Marius Trabitus by name. Sort of round, but none the less solidly built, and definitely past middle age, he had sharp eyes and a crisp, yet measured way of speaking, as though no words passed his lips until he had examined them carefully to make sure they conveyed just what he wanted them to convey, and no more.

"Glad to be of help," he said, his eyes taking in the room, with more than one glance towards the platters of food on the table. "Glad to be of help. You want me to tell you about my encounter with the shade of Julius Caesar?"

"Yes, Senator. If you please."

"It was frightening, frightening," Trabitus said, sitting down across from my master and helping himself to a couple of dates from the platter. "It happened about a week ago now. It was late, quite late. I was in the anteroom to General Vespasian's audience chamber - the general dislikes calling it a throne room, and indeed he has no throne in the room waiting to speak with the general, when suddenly he appeared before me. Just - appeared - like that -" he waved a pudgy hand through the air to show what it was like.

"Who?"

"Why great Caesar's ghost, that's who. One second the room was empty, and the next, there he was. 'Vespasianus,' he called, 'beware the Ides of October.' And he sighed mightily, and dripped blood from gaping wounds in his toga. He stared at me, and I stared at him. I thought of trying to go and touch him, but I seemed to be rooted to the floor. I did not feel fear, but a sort of tremendous awe, as though I were in the presence of something greater than a mere mortal. And then all at once he disappeared, like blowing out a candle. And - you won't believe this - when I went to look, there was no blood on the floor! It was then that I felt fear. And then, like an echo from beyond, came the words again, 'Beware the Ides of October!' "

Quintilian leaned forwards. "And what did you do?"

"I just stood there. I mean, after all, what could I do?" Quintilian nodded. "What, indeed?"

"Shortly thereafter a page came for me to take me in to speak with General Vespasian, and I told him what had transpired."

"The page or General Vespasian?"

"Both, I'm afraid. And probably everyone else I saw for the next few days. I tell you, it quite unnerved me."

"I can believe that. And what did you make of it?" "What did I make of it?"

"Yes. What do you think it meant?"

Trabitus looked as if he were about to say something, and then thought better of it. "I don't know," he said finally. "I mean - it's not for me to say."

Quintilian nodded. "Yes," he said. "Very wise. You just report what has happened; let others mull over its possible meaning."

Trabitus stood up and took one last fig. "I heard about the young lad who was killed," he said, shaking his head. "A small knife is of no use against a ghost." He ate the fig. "I suppose a large knife wouldn't be much help, either."

"I think certain sorts of incense and the reciting of the proper prayers are usually regarded as efficacious," Quintilian said. "But there is a lack of general agreement on just which sorts of incense and which prayers to use."

Trabitus looked dubious. "I suppose you're right," he said. "I hope I've been of some help."

"I believe you have," Quintilian told him. Trabitus glided from the room, and Quintilian turned to look at me.

"Yes?" I asked.

He put his knuckle to his lips and stared off into space, working on the phrasing of what he was about to tell me; I recognized the signs. "When the improbable passes over into the impossible, the wall of truth has been breached," he said.

"I can't write it down," I told him. "Very nice, whatever it means, but I can't write it down."

"But it doesn't have . . . yes, I suppose you're right. See if you can remember it to include it in my collection of aphorisms for the young."

"Yes, sir," I told him.

Our next guest stomped in and declared "Decurion Carlus to see Investigator Quintilian as directed!" and then came to attention, standing as rigid as a marble column before the makeshift desk. He was a big man - not tall, but big in every other dimension. His arms were as big around as a wrestler's thighs. It would take two normal men with their arms outstretched to encompass his chest. His neck was so thick that his head seemed to emerge from it instead of being supported by it. His nose was flat, his ears were small and hugged the side of his head, and an ancient scar that ran from his chin to his right temple made his face look lopsided.

"Sit down, Decurion Carlus," my master said, gesturing towards the chair Carlus stood next to.

The massive decurion lowered himself gingerly into the chair. "I am here about the lad who got killed last night," he said.

"Septius?" Quintilian asked.

"That was his name, yes."

"Do you know how he died?"

"I do not, unfortunately. He was a good lad. Wanted to be a legionary. Would have made a good one, too; intelligent, cool-headed, took orders well. The last I saw of him, he was chasing a ghost." A plain, matter-of-fact statement, with no more emotion behind it than if he'd said, "The last time I saw him he was eating a fig."

"Ah," Quintilian said. "When and where was this?"

"At the start of second watch. I had assembled the guards to post them - relieving the first watch, you know - when a figure that looked a lot like Julius Caesar, from the busts and coins and such, you know, appeared above us -"

"Above you?"

"On this sort of balcony. Our guard room was Nero's music room, or some such, and there's this small balcony sticking out of one wall. Well, this apparition, or whatever, starts yelling about the Ides of October, or some such. I pay it little attention, as I have to get my men posted. And besides, the way I figure it, if I act like it don't mean anything, why then the lads won't take it seriously. They'll think it's some sort of joke, like. Otherwise, if they take it serious, well, it could mean trouble. Most of the lads are from the northern provinces, and they're a superstitious lot."

"You don't believe in ghosts?"

"I don't know about that," Carlus said. "But I don't believe they've got any business interfering with my men, when I'm trying to get them posted for guard duty."

"A sensible attitude," Quintilian said, nodding.

"Well, I give the men an 'eyes forwards', and start marching them to their posts, when young Septius, who was in there repairing some lacings on his sandals, suddenly jumps up and says, 'That ain't no ghost! I'll see about that!' and goes racing out of the room. I don't know what got into him. Maybe he saw something that I didn't."

"That could be. Do you know where he went?"

"He was heading towards the stairs to the balcony when last I saw him. When I got back from posting the guard, he was gone, and I didn't hear any more about him until somebody came in this morning and said they'd found him dead."

"What did you think?"

"I didn't think it was no ghost. What use would a ghost have in stabbing a man to death? Not the way of ghosts at all, from what I hear."

Quintilian smiled. "What use, indeed," he said. "You've been a big help, and I thank you."

"A nice lad," Carlus said. "Sorry about whatever happened to him. You bring that ghost forward and my lads and I will take care of him good."

"I'll try to do just that," Quintilian told him.

We saw several more people in the next hour or so, but they added nothing to what we already knew. Of course, as far as I could see, what we already knew added nothing to what we already knew. On reviewing that sentence I can see that it makes little sense, and Quintilian would chastise me for writing it and tell me to write, clearly and concisely, exactly what I mean. What I mean is that we had interviewed over a dozen people, and learned that the ghost of Julius Caesar appeared at times, gave a doleful warning about the Ides of October, and then disappeared. Which is what we knew before we interviewed the first person.

When the last person had been interviewed, Quintilian rose from his seat and began pacing back and forth across the room, his head down, looking at the floor in front of him. I scurried over to the side of the room and sat on the floor, my back against the wall, to keep out of his way. My mentor thinks best in motion, and I try to do nothing to disturb his thinking.

He stayed in motion for some time, gesticulating in strange and wonderful ways as he paced, grabbing thoughts and ideas from the air and assembling them into various patterns, until he found one that made sense out of the facts of the case. He had explained this to me many times, and I had watched him perform this magic in many different cases, usually shortly before the start of a trial. I say "magic" because, when I try a similar process, all I grab is thin air, and all I get is a headache.

Finally he stopped pacing and sat down. "If something is impossible," he said, "why then, it is impossible. Discard it, and you are left with the truth."

"What does that mean?" I asked.

He turned, seeming a bit surprised to see me squatting there against the wall. "It means I see a way to catch a ghost."

I shuddered. And, mind you, I'm not at all sure I believe in ghosts. But after the stories we had just heard . . . "Is that wise?" I asked.

"Not only wise, but necessary," he told me. "It will require a long strand of wool, and, just in case, a man with an axe." "Pardon me?" I said.

"That centurion - Sabatinus - should be waiting somewhere outside the door. Fetch him for me."

I went into the corridor and beckoned to the centurion, who was sitting on a chair he had acquired from somewhere, talking with two of his troopers. Sabatinus fairly trotted into the room. "It's approaching dinner time," he said. "I would like to let my men go for their meal, if you can spare them for an hour or so."

Quintilian pushed himself to his feet. "Let us wind up this business," he said, "and then, no doubt, your men will be able to feast."

"Ah!" Centurion Sabatinus said. "Then, honourable Quintilian, you have been able to make some sense of the stories you have been listening to?"

"Send one of your men for an axe," Quintilian told him, "and have him meet us at the anteroom where that poor lad was found dead."

Sabatinus sent one of his men off to find an axe, and he led the rest of us back to the door to the anteroom. Which was a good thing as, with all the twists and turns we took in this gigantic maze of a palace, I doubt whether we could have found it on our own.

"You wait out here," Quintilian told us. "I don't want you disturbing the air in the room." And with the final comment, "I could be wrong, but I think not," he went inside the little room by himself.

We waited. We could hear pounding, tapping and thumping from inside for a while, and then my master stuck his head out the door. "I need more light," he said. "Bring me some lamps."

Sabatinus's men scattered about and found four lamps, returning with them about the same time as the trooper who had gone for the axe rejoined our little band. Quintilian took the lamps inside the room and closed the door. We waited some more. This time there was nothing but silence from inside the room.

Quintilian opened the door. "Come in," he said. "We won't need the axe. Well, perhaps we will need the axe; bring it along."

We followed him back into the room. "Well, I'll be -" Centurion Sabatinus said.

At first I didn't see anything different, except for the circle of oil lamps burning on the floor, casting their varied shadows on the walls. And then I saw that what I had taken to be a shadow was actually an opening in the side wall. Starting at the floor, it was about two feet square, and seemed to lead into some sort of tunnel. The part of the wall that had concealed the tunnel had opened inward, and was now flat against the tunnel's side.

"Did you know there were secret passages within the palace?" my master asked Sabatinus.

"There was a secret exit," the centurion told him. "It was the way that Nero escaped the mob that was hunting him, after hiding for a day. We have closed it up. How did you find this one?"

"Logic said there had to be an entrance to this room aside from the two doors. Even a ghost couldn't take a body through solid walls."

"But a man could have passed the guards without attracting much attention," Sabatinus said. "Besides, in the middle of the night, there was a good chance the guards would be asleep - or at least dozing."

"Yes, and a man might chance it. But I doubt whether a man carrying a body would feel the same. So the most logical answer was that there's a hidden entrance to this room. At first I tapped all the walls, but I couldn't detect any difference in sound. So then I pulled a strand of wool from the hem of my toga and lighted the end from one of the lamps. It burned with a thin wisp of black smoke. I slowly moved it about the room, near the walls, until I saw the smoke deflected by a slight draught. After some experimentation I found that the panel unlocked by pushing in on a leaf in the wall painting, and then I could slide it open. So I didn't have to call on the axeman."

Centurion Sabatinus nodded. "Very logical," he said.

"Let's see where this doorway leads," Quintilian said.

"Wait," said Sabatinus. "I'll go first - that's my job." Pulling his gladius from its scabbard, he held the short sword in front of him in his right hand and an oil lamp in his left, and crawled head-first into the tunnel. Quintilian followed, and then the three troopers, each with one of the oil lamps, and the last carrying the great double-bladed axe that he had brought. I followed in the rear, and glad of it. I am not made for fighting. And yet nothing could have stopped me from following along to see the end to this ghostly mystery.