"I am on the emperor's business," the decurion replied sternly. "For me, he will arise."

There was a time, and not so long ago, when having a squad of the emperor's praetorian guard appear at your front gate was a good reason for fleeing out the back gate, no matter how noble your family or how high your position. But the days of Caligula and Nero are in the past, and our present emperor is not known for intemperate rages or random murders. Still, the gods themselves have been known to fly into sudden fits over minor misunderstandings, so to my mind a sudden summons from Emperor Vespasian might not be cause for flight, but a little moment of sheer terror might be understandable.

The decurion told my mentor, who came grumbling to the door of his bedroom, that his orders were to take Quintilian directly to the emperor, and as quickly as possible. With that, Quintilian dressed, splashed some water on his face, threw a cloak on over his toga, and said, "Lead on!"

I was already dressed, so I grabbed my sack of fresh wax tablets and fell in behind my mentor. I was so accustomed to accompanying Quintilian everywhere he went that we were halfway to the imperial palace before I realized that I had not been included in the summons, and Quintilian had not actually asked me to join him. Quintilian strode along, impatient with the measured tread of the guardsmen. I scurried to keep up, the sensation in my left leg, crippled from a childhood illness, progressing from a dull ache to a sharp, jarring pain with each step. But I have learned to live with pain.

The thoughts that were a great jumble in my head were of more concern than the pain in my leg, and I will admit they were unworthy of the lessons I have learned at the feet of the great Quintilian. If my mentor had somehow incurred the emperor's displeasure, would Vespasian throw him into a dungeon, or send him home to commit honourable suicide, or have him dispatched by the short sword of, perhaps, this very decurion that was taking us to the court? And, since I was with him, would the emperor include me in his displeasure, however expressed, as a matter of course?

We arrived at the east gate of the Golden House, the great palace that Nero had built (although he had died before it was finished, to the relief of all Rome), and were rushed through a series of rooms and courtyards, going deeper and deeper into the inner palace. At each doorway the decurion lifted his left hand, exposing to the guard a sigil he kept cupped in his palm, and announced, "At the emperor's command!" And the guards stood aside as we hurried through. Shortly we reached what I assumed were the private living quarters of the emperor himself. There were guards scattered all through the vast structure, like golden raisins in a porridge, but here they were clustered closer together and they stood straighter, and their armour was even more highly polished.

The decurion handed us off to a gold-plated centurion, amid much saluting and foot-stomping, and the centurion clasped hands with Quintilian. "They call me Sabatinus," the centurion told him. "I am to take you directly to the emperor."

"Do you know what this is about?" Quintilian asked.

"Not a clue. Have you met Vespasian before?"

"Once, briefly. A ceremonial occasion."

"Then for your information: he dislikes being called 'emperor', or 'Caesar', or 'princeps', or any of the other titles he has to use in public. Call him 'General Vespasian', or just 'General'."

Centurion Sabatinus took us through a great hall and we entered a corridor wide enough for a goods wagon to pass along without scraping the sides and long enough to require a lusty shout to be heard at the far end. Not that I attempted a lusty shout - that was just my impression. There were a pair of great bronze doors a comfortable distance along the corridor, flanked by two glittering guardsmen, but the centurion skirted by them and took us instead to a small black door near the corridor's end. The guardsman at the door intoned, "They are both in there," under his breath, and pulled it open.

We entered. The room was small, plainly furnished with a flat board for a desk, several camp chairs, and a nest of cubbyholes along one wall filled with scrolls and rolled documents of various sorts. And they were indeed in the room. Sitting behind the flat board of a desk, bent over a lengthy scroll, his body squat and hard, his face the square, blunt, honest face admired by his legionaries, was Titus Flavius Vespasianus, subduer of the Britains under Emperor Claudius; conqueror of the Jews under Emperor Nero; and now himself Emperor of Rome and sole ruler of the Roman Empire, which encompassed most of the known world. Standing by his side, holding a partially unrolled scroll, was his 20-year-old son Domitian, Titus Flavius Domitianus, who had been his father's presence in Rome while his father was in Judea, and was now Vespasian's trusted right hand.

I looked over Domitian carefully, for I had heard much about him. He was young; younger even than I. He was handsome, with a square jaw and a shock of dark, curly hair. His feelings, whatever they might be, were reserved and did not show on his face, which was a mask on which a slight, disdainful smile was the only visible emotion.

Some say Domitian was jealous of his brother's success. Vespasian's older son Titus had been left behind in Judea to finish the job of subduing the Jews, and had taken and sacked their capital city of Jerusalem and burned their temple the year before, ending once and for all the incessant bothersome revolts of these religious zealots with their "Our god is better than any of your gods" fanaticism.

Some of those who claimed to have an ear into what happened inside the palace walls, those who studied the currents within the imperial household with the diligence of nervous lovers interpreting their beloved's every sigh and gesture, said with a sneer that Domitian was just as glad not to be facing the rigours - and dangers - of a martial campaign.

There are many who seem to know, and will be glad to whisper to you in great detail, the secrets of the palace; yet I have observed that those who actually do know seldom can be persuaded to speak. That last sentence has a nice flow. I believe I have just written an aphorism of some worth. I would read it aloud to Quintilian, but he would assuredly first compliment me on it and then spend some time telling me how to improve it. And most galling of all: he would be right. I think I shall not show it to him at this time.

The centurion came to attention by Vespasian's desk. "Marcus Fabius Quintilianus, as directed, General."

Vespasian looked up. "Ah!" Then he turned to look at me, and I believe I turned white with fright. "And who is this?"

Quintilian stared at me, I swear by Janus, as though he had never seen me before "My scribe Plautus, General," he said finally.

"A scribe, eh?"

"I also use him as my personal assistant," Quintilian added.

"I see." Vespasian glared at me. "You may assist the honourable Quintilian, if he needs your assistance," he told me sternly. "But you are not to scribe a single word of what transpires here. Is that clear?"

"Yes, your, ah, general," I managed to get out.

"Good." Vespasian made a gesture, and the centurion saluted and left the room. "I have a problem," the emperor of all the known world told Quintilian, lacing his hands behind his head, leaning back in his chair, and staring at Quintilian through half-closed eyes, "and, from all I have heard of you, I am depending on you to discover the solution for me. Pull over one of those camp chairs, and enlighten my son and me with your wisdom." He spoke in a measured voice, as though each word were weighed before it was uttered. I suppose that if I knew that my every word would be dissected, parsed, examined and discussed by a sycophantic, back-stabbing collection of Roman courtiers, I, too, would get into the habit of speaking with great care.

Quintilian moved one of the leather-covered camp chairs over to the desk and sat. I squatted on the floor next to him and restrained myself from pulling a wax tablet from my bag.

"I thank you for your faith in my judgment," my master said, "but I'm not sure I should thank whoever passed on such a glowing account of my small abilities. I am a rhetorician, with some success in pleading cases before the courts of Rome. If it is skill with words you require, I shall be honoured to write speeches for you, as Seneca is said to have done for Nero. But I know nothing of statecraft, or of warfare, or of the numerous intrigues that doubtless cloud the imperial court."

"And yet when I ask the courtiers who infest this place to find me the wisest man in Rome, those who did not immediately drop to the floor and chant 'you are, oh mighty Caesar,' seemed to think that, since Seneca died, it is probably one Marcus Fabius Quintilianus. I also had my staff ask of various learned men whom they would recommend for solving an arcane problem, and your name was mentioned frequently."

Quintilian smiled a thin smile. "These must not have been friends of mine, General," he said. "My friends would have assured you of my almost invincible stupidity."

"He is the one!" Domitian interrupted, leaning forwards, his knuckles on the desk. "I told you, father, what the Sybil said." He turned to Quintilian. "My father and I have chosen you for this task. You are expected to comply!"

Vespasian raised a hand. "I apologize for my son," he said. "He has not yet learned that there are some people to whom you must give orders, and others from whom you may request, but not require, assistance. If you do not feel you are fit for the task, it would waste both of our time for you to attempt it."

Domitian swallowed and sat down by the side of the desk.

"And just what is the task, General?" Quintilian asked.

"People here in the palace; guards, courtiers, and others, recount that they have been seeing a ghost wandering about these halls. Or so they say. I want you to find out just what it is they are seeing and, if it is a ghost, convince it to go away. And, for that matter, if it isn't a ghost, convince it to go away."

"A ghost?"

"Just so," Vespasian said, looking annoyed. "And not just any ghost. The shade, to be precise, of Gaius Julius Caesar." I stifled an exclamation.

"Julius Caesar? He's been with his fellow gods for over a century now," Quintilian said.

"A hundred and twelve years," Vespasian affirmed. "Why, you may ask, if he were to come back, would he return to Nero's palace; a place he'd never seen in his life built by a man he'd most assuredly despise? I have no answer. But that doesn't stop him from walking these halls, at least according to those who have seen him."

Quintilian nodded. "Reports of ghosts should be taken seriously," he said. "But would it not be better to get Pliny the naturalist to investigate this? I understand he's writing some sort of vast book on these sorts of natural phenomena."

"We sent someone to ask his advice," Domitian said. "He's at his estate in Como. He recommended you."

"Ah!" My master nodded thoughtfully. "And just what was it that the Sybil said?"

Vespasian sighed. "My son went to Cumae to consult the Sybil about two weeks ago. He asked my permission, and I complied. I thought a favourable prediction would end the mutterings."

"The mutterings?"

Vespasian made a gesture to his son, who took up the story. "A figure wearing a senatorial toga with a laurel wreath circling his head has been seen wandering throughout this building at all times of the day and night - but mostly at night. He disappears when anyone attempts to approach. Those who have seen him report that he looks like the busts of Julius Caesar. I think every Roman has a good idea of what the great Caesar looked like."

Even so," Quintilian agreed.

"Some even report seeing open wounds on the figure, such as Caesar received on that fateful Ides of March," Domitian continued. "And the blood dripping on the ground. But no blood has been found when the area was examined."

"I see," Quintilian said. "So we have a disappearing spectre who looks like great Caesar. How long has this been going on?"

"At least two months. Perhaps longer."

"Have either of you ever seen it?"

Vespasian shook his head. His son said, "No, we have not been so fortunate."

"So. And why are the ruler of the Roman Empire and his son so concerned about this spectre flitting about the palace that they feel the need to ask for my poor services?"

"Two things," Vespasian said. "First, the shade has begun to speak."

"Speak?"

Domitian stood up and leaned over the desk. " 'Beware the Ides of October,' " he recited. "That's what the fool thing has started to say. Bah! If it was Caesar, it'd probably be saying 'where are the girls,' or more likely, 'where are the boys?' "

"Now, son," Vespasian fixed his younger son with a stony glare. "Those are vile calumnies spread by Caesar's enemies when he had joined the gods and was no longer around to defend himself. Jove only knows what they'll be saying about me when I, ah, ascend."

"Beware the Ides of October," Quintilian repeated. "Not good."

"No." Vespasian grimaced. "And you know how superstitious the average Roman is; always looking for portents and appealing for help from one god or another. When I embark on a campaign I must have the legion's soothsayer inspect the entrails of a pigeon and a rabbit to make sure the signs are favourable. My troops might refuse to move if I did not."

Something about Vespasian's glare as he said that told me that the soothsayer knew in advance just what he'd better find in those entrails.

"It makes me a prisoner in this blasted palace of Nero's," Vespasian continued. "I want to move out. I planned to move out. This gilded claptrap is too ornate - too Nero - for me. Now that it's finally finished, I plan to turn it into an imperial forum, or a series of temples to the more important gods, or something. I plan to build myself a simple - well, comparatively simple - imperial abode by the Field of Mars. But I cannot move with this spectre hanging over me. I cannot seem to be moving from fear. If I leave while this is going on, my troops will lose respect for me. And there are still followers of Otho or Vitellius about who would just as soon see me dead. And if -that happens we'll have another year with three or four emperors, one after the other, bim, bam, like that, fighting to stay in power. And Rome couldn't stand it."

"So the ghost of Julius Caesar is keeping you in Nero's palace by threatening your death. I assume that's how you interpret the 'Ides of October' business?"

Vespasian shrugged his broad shoulders. "How else?" Quintilian nodded. "And that's why your son consulted the Sybil?"

"It was right after I first heard of the 'Ides of October'," Domitian said. "I went to Cumae with a small bodyguard, and paid the priests for an audience with the Sybil. I did not tell them who I was."

Sure, I thought, just some random nobleman guarded by a troop of the praetorian guard. But I kept my mouth shut.

Domitian continued, "The priests kept me waiting for most of the day. Then, as dusk fell, I was taken into the cave. 'Sybil,' the priest said, 'this is Vergilus,' for such is what I had told them was my name."

"What did the Sybil look like?" Quintilian asked.

"The cave was dark, and lit by torches, and it was difficult to tell," Domitian said. "One moment she looked young and beautiful - unbelievably beautiful - with long, dark hair, and a slender, sinuous body. And the next moment she looked old, unbelievably old, and wise beyond the knowledge of mortal men."

"Ah!" Quintilian said, running his forefinger along the side of his nose. "Tell me, did you smell anything?"

Domitian thought for a moment. "Some kind of incense. Perhaps it was from the smoke coming from a vent in the rock. It made my head spin."

"Ah!" Quintilian said again.

"She looked at me for a long moment. And then she said to me, 'Hail, ruler of men.'

" 'I am no ruler of men,' I told her.

" 'You are what I say you are,' she said. " 'You have come about a Caesar,' she said, 'the Caesar that is yet to be concerned about the Caesar that was.' "

"Indeed?" Quintilian said.

Domitian nodded. "I was startled. I am no fool; I know the priests could have guessed who I was from my raiment, or from the guards I travelled with. But I told no man the purpose of my quest."

"And what was it she told you?"

"She seemed to go into a trance. For a long while she said nothing. Finally she said, she sort of chanted, The past returns through the wiles of men It is not hard to die Saying does not make it so The highly regarded ignorant one will cleave the knot And Caesar shall create a school in his answer"

"This verse," Quintilian asked, "is it precisely what she said?"

Domitian nodded. "A priest sort of hides in a corner and writes down everything she says. He wrote out a copy for me."

"I don't know what else it may mean," Vespasian said, "but you are marked by your own words. It is clear that you are the highly regarded ignorant one who will cleave the knot."

Quintilian thought for a moment and then looked up. "You said there were two things."

"I did." Vespasian turned to his son. "Domitian, show our learned friend the other, ah, thing."

"Very well." Domitian stood up and gestured for us to accompany him. We went a short way down the corridor and entered a short separate hallway leading to a single door. A guardsman before the door stiffened into a living statue of The Perfect Guardsman At Attention at our approach.

"At ease, guardsman," Domitian said. "Has anything happened during your watch? Anything at all?"

"No, sir," the guardsman spat out between clenched teeth, his face turning red from the effort of talking without moving his lips.

"Thank you. Remain at ease." Domitian pushed open the door. "This is - was - the anteroom to Nero's throne room," he told us. "My father chooses not to use a throne room, but has a small audience chamber in another part of the palace."

The anteroom was small, the walls decorated with a continuous painted scene of woodland beauty, including several scantily clad nymphs darting among the trees. There were two doors: the door we had come in, and a door across the room leading to the throne room. Whatever furnishings the chamber had held during Nero's time had been removed. It was now bare, except for one, lone, corpse lying in a grotesque heap in the middle of the floor.

"He was found early this morning," Domitian said. "The throne room is occupied through the night. It is used as the guardroom for posting the night guards. The hallway is under guard all night. Nobody saw the lad go in or out. And yet, here he is."

The corpse was a young man in a white tunic and sandals; by his dress not a slave, but not a high-status Roman either. Possibly a freedman servant. He had been stabbed several times in the chest and neck. There was surprisingly little blood, but the victim had apparently used what there was to draw the number XIII on the floor above his head with his right forefinger as he was dying.

"Thirteen," Quintilian said.

"The Ides of October fall on the thirteenth," Domitian said.

"Yes," my mentor agreed. "That would be it, of course. Who is the dead lad?"

"One of the pages. Name was, I believe, Septius." "What were his duties?"

"I have no idea. You can ask."

"Who saw him last, that is, when he was alive?"

"You may ask that, too."

Vespasian appeared in the doorway behind us. "Well?" he asked.

Quintilian turned to him. "This lad was not killed by a ghost," he said.

Vespasian sighed. "You know that, citizen Quintilian, and I know that. But when word of this gets out, it will be hard to convince the mob. Including, I am afraid, most of my guardsmen."

"All right, General. I will try to resolve this ghostly business for you. After all, we cannot make a liar of the Sybil. First I must spend some time examining this poor lad's body. Then I must see the various places where this apparition has appeared. And then I will speak with all those who claim to have seen Caesar's ghost, and particularly those who have heard it speak."

"Yes," Vespasian agreed. "And I must find out who the lad's parents are. They must be notified. Death is always cruel and often unnecessary, even in battle. This -" he gestured at the body "- this is a waste." He looked down at the corpse and shook his head. "I sometimes think that the only death that is not difficult to accept is your own."