There were times when Tero found his friend’s evasiveness maddening. This, it seemed, was going to be one of them. “No,” he said, “you never did. Why do you see fit to impart this bit of information to me now?”

“I am coming to that, never fear. You see, Diodoros himself was learning his skill in Alexandria when Heron son of Ktesibios was at the height of his fame.”

Tero had to admit he did not know the name.

“Do you not? A pity; he was a remarkable man, probably one of the finest machine makers the world has ever seen. Diodoros was fascinated by his contraptions, and he never tired of talking about them. Really amazing things: a device for dispensing sacramental water that worked only when a copper was inserted, a trumpet made to sound by opening a nearby door, bronze animals that moved like live ones, and many other things.”

“He sounds like a sorcerer.”

“No, he was an artificer and nothing more. One of the things he made, not really more than a toy, was what he called an aeolipile.”

“All of this must lead somewhere, I suppose. What might an aeolipile be?”

Kleandros explained: a water-filled cauldron was fitted atop with a hollow ball mounted on a hollow tube. Directly opposite the tube’s entrance into the ball was a pivot, which was attached to the cauldron’s lid. The ball itself was fitted with bent nozzles; when a fire was lit beneath the cauldron, steam traveled up the hollow tube and out through the nozzles, making the ball spin merrily. “Do you see what I’m getting at?” the doctor asked. “In this device the force of the steam escaped continuously, but if some way were found to block it up for a time and then release it all at once, it could give a little metal pellet a very strong push indeed.”

Tero took another pull at his wine while he thought. The idea had more than a little appeal, for it gave a rational picture of how the killing might have taken place. Still… “A cauldron, you say. How big a cauldron?”

“I have no idea. I’ve never seen the machine in action myself, only heard Diodoros talk about it.”

“Somehow I find it hard to imagine Clodius Eprius letting anyone set up a cauldron in the middle of the room and then aim a little ball at him. And whoever would be using it would have to wait for his water to boil before it would go off, wouldn’t he?”

“I suppose so,” Kleandros said sulkily.

“Not only that, anyone hauling a cauldron through the middle of Vesunna would get himself noticed. Even if I don’t know what killed Eprius, I can tell you a couple of things about it: you can use it right away, and you can carry it around without having it seen. I’m afraid your whatever-you-call-it misses the mark both ways.” Seeing his friend’s hurt expression, Tero went on. “If you could make one big enough, it might make a good ballista, though.” I wonder why our generals never thought of anything like that, he thought, a little surprised at himself.

“Your logic is convincing,” Kleandros said, adding, “Damn it!” a moment later.

“Let’s give up on the weapon for now,” Tero suggested. “It matters less than the person who used it. If we had some way of knowing who he was, we might catch him, thunderbolt thrower or no.”

“A good point,” Kleandros said. “Whoever he was, we can be fairly sure he was from outside the empire.”

“Why do you say that?”

“We know of no weapons to fit the bill within our land, do we? Also, why would a citizen need to carry coins that weren’t genuine but would pass one by one? If they are true gold, that only makes the argument stronger.”

“A spy!”

“You may have something there. But who would want to spy on Vesunna, and why?”

Thro opened his mouth for a reply, then realized he did not have a good one. No one had ever seen a German in the town, and Parana was at the other end of the world. Besides, he was sure neither the Germans nor the Parthians had weapons that could blow large holes in men’s heads. If they did, they would have used them on Roman soldiers long before. In fact, anyone who had such a weapon could master the world, and surely would have done so by now. It made no sense at all.

What other foreigners were there? There were nomads south of Roman Africa, and others east of the Germans. There was an island off the coast of Britain, but it was full of savages, too. There was-“Men from Atlantis, perhaps?”

“My dear Tero, I would be the last to deny Platon was a man of godlike intellect, and the Timaios has always been one of my favorite dialogues. Still, as far as I can see, in it he invents Atlantis in order to portray an idealized way of life. And, as Aristoteles said, ‘He who invented it destroyed it,’ for, if you’ll remember, Platon says it sank beneath the waves thousands of years ago.”

“That’s a pity, because I don’t see how a spy could come from any country we know well.” He explained his reasoning to the doctor, who nodded.

“Where does that leave us?” Kleandros asked.

“Right where we started-ramming our heads into a stone wall. A plague on it for now. Did you bring your Iliad with you? I’d sooner bend my brain around that for a while.” Slowly but surely, over the course of years, Kleandros vas teaching the vigil to read Greek; most cultured citizens of the empire were bilingual. Tero spoke Greek fairly well: though more elastic, its basic structure was much like that of Latin, and there were more than a few similarities of vocabulary as well. But Homer was something else. His hexameters were splendid and his picture of the heroes of the Trojan War supremely human, but his antique vocabulary and archaic grammatical forms often made Tero want to tear his hair.

Line by line they fought their way through the opening of Book Sixteen, where Patroklos begs Akhilleus to let him borrow his armor and drive the Trojans from the ships of the Akhaians, which they had begun to burn. Akhilleus, hesitant at first, assented when he saw the fire going up, and

“Patroklos armed himself with shining bronze.”

“I hate these funny-looking datives,” Tero said, but went on:

“First he put well-made greaves on his calves;

They had guards of silver on them.

Then on his breast he put the cleverly made shining

Corselet of Aiakos’ swift-footed scion.

He slung his silver-nailed bronze sword from his shoulder,

And after it a great stout shield as well.”

“Bronze, bronze, bronze!” Tero said. “Bronze this, bronze that. One cohort of my legion could have gone through all the heroes of the Trojan War, Akhaians and Trojans both, in about an hour and a half. Ten years? No wonder it took them ten years with tactics like theirs. They run at each other, throw their spears, and then start looking for rocks to fling. And nobody cares about the fellow next to him until the poor sod gets a spear in the groin. Then they fight over his armor, not him.”

“You have the soul of a turnip,” Kleandros said; he had heard Tero’s complaints many times. “That we are better at killing people than they were in Akhilleus’ day is no cause for celebrating.”

“Nevertheless, I wonder what shining-helmed Hektor would have thought if one morning he woke up and found my old legion around his walls instead of those Akhaian cattle thieves. Can you imagine it? Earthworks, siege towers, catapults, rams. He couldn’t have held that town three days against us. I think I’d have paid money to see his face.”

“He probably would have been like Afer, convinced all the gods were angry at him.”

“And yet we would just have been men with skills he didn’t have, not demigods or heroes. It’s very strange.” Tero returned to his home and plowed on doggedly even after his attention began to wander. The truth was that he did not want to think about Eprius’ corpse, though he suspected he would see it in his dreams for years to come. Crimes were hard enough to solve at any time; but this one had an impossible wound, an unknown but highly potent weapon, a good many cleverly counterfeited aurei, and, to make matters worse, no visible motive. “What verb does lelalestho come from?” he asked Kleandros.