Psellus smiled. Ah, he thought, Specification. Military technology was the one exception to the Republic's most inflexible rule. Even so, the siege engines (drawn to scale in meticulous detail, with numbered parts) were essentially the same as the ones he'd seen on the walls a week ago, when he'd made a rather self-conscious tour of inspection. Whoever Varus Paterculus was, he had an excellent eye. After scanning a couple of pages, Psellus reluctantly skipped the rest of the chapter, and moved on to:
Of the various devices whereby a city may be defended from the said engines.
He tried to read on, but he couldn't. The diagrams, he assumed, were supposed to represent fortified cities, seen from the air; but they made no sense. On each page was a shape; abstract, symmetrical, perfect. The simplest were like ornate, many-pointed stars. Others were like gears from some extraordinarily sophisticated machine, or blades for a circular saw designed to cut through some desperately resilient material, or frost patterns on a pane of glass. After staring at a dozen or so, Psellus leafed forward until he found text.
The explanation helped, though not much. The basic theory was that a city under siege needed to be protected against siege engines and sappers. A plain, straight wall meant that the defenders' engines and archers had a very limited arc in which they could shoot down at the enemy, who would be safe in any event once they reached the foot of the wall. To give the defenders a better field of fire, it was desirable to build projections at regular intervals. The simplest ones were triangular, like the teeth of a saw. These offered opportunities to shoot straight ahead, and also sideways, at attackers venturing into the V-shaped gaps between the projections. Faced with these, however, the attacker would inevitably react by digging trenches, zigzagging across the open ground in front of the city like a mountain path, so that his army could approach the walls in safety. This could be countered by making the shape of the projections more elaborate. Instead of a simple V offering only three directions to shoot in, the defender's mantlets and ravelins (the terms weren't explained) should be pentagonal or hexagonal, multifaceted as a jewel, so that wherever the enemy led his trench, one face of the defensive works should always be in line with it and able to shoot down into it. Furthermore, since a determined attacker with plentiful manpower would sooner or later over-run or undermine even the best defence, there should be two, three, or even four concentric rings of fortification, banked up on mantlets and toothed with ravelins so that the inner rings could harass any assault on the outer rings by shooting over the lower defenders' heads. The best material for building such works was not stone, which shattered under the impact of heavy missiles, but sand and soft earth turfed over and retained inside simple shells of treble-skinned brick; such defences being capable of withstanding intense bombardment without shattering, and also frustrating the sapper, since an attempt at undermining would simply result in a fall of earth that would stop up and smother the sap…
Psellus closed the book. Sooner or later-sooner, he was very much afraid-he'd have to open it again, and try and wrap his feeble mind around it. But not now. More than anybody else in Mezentia, he flattered himself, he knew his own limitations. If he tried to read any more, the tremendous weight of information would cave in on him and bury him, like the wretched sappers… Well, he said to himself, I asked a question. I can't really complain about getting an answer, even if it's so huge it'd take a hundred men a lifetime to understand it. He remembered a story he'd heard when he was a boy, about a tiny doorway in the side of a mountain that led into another world; vast plains and mountains under unlimited skies, all contained inside a little door. Closed, the book was just a flat brown thing; you could put a couple of reports on top of it and bury it completely, so you wouldn't know it was there. Open, it led to something monstrous and huge; reading it, he thought, would be an undertaking on a par with invading a large and hostile country, and once you ventured inside, there was more than a chance you'd never get out again.
He stood up, opened his door and called, "Hello."
Simuo Catorzes appeared from just out of sight. "What can I…?"
"Come in here," Psellus said. "On the desk, look."
Catorzes looked sideways at the spine of the closed book, and said nothing.
"Did you read that one?"
No words, just a nod. Then: "I didn't include it in the epitome."
"Oh." Psellus frowned. "Why not?"
A slight pause before Catorzes answered. "It's very old," he said. "Out of date."
"I don't think so," Psellus replied mildly. "I think it looks very useful."
There was resentment in Catorzes' eyes, working itself up into hatred. "If you say so," he said. "I'll add it to the-"
Psellus sighed. "No, don't bother," he said. "You've got enough to do, I'll look at it myself. But I want you to search through the books of maps; I seem to remember seeing plans of towns and cities-quite old, some of them. I want to know if anybody's ever actually built a city with all those sticking-out bits."
Catorzes smiled; just a hint of malice. "Ravelins," he said.
"Exactly, yes. What I'm getting at is, was all this stuff ever real, or is it just a lot of ideas and complicated drawings? That's the trouble with books," he added bitterly. "There's no way of knowing whether what's in them is valuable practical advice or just someone's flight of fancy." He stopped, as a strange thought struck him. "Two hundred years ago," he said. "Do you know much history?"
"Me?" Catorzes scowled, as though he'd just been accused of a particularly disgusting crime. "Well, yes, I suppose so. As much as anybody else does."
"Ah." Psellus smiled. "Probably about as much as I do, then. And it's just occurred to me that I know hardly anything about what things were like two hundred years ago. Maybe there were cities built like the ones in that book, only we don't know about them because they aren't there any more. I have an idea that the Republic fought a great many wars a few centuries ago, mopping up the little city states that used to exist hereabouts, until only Eremia and the Vadani and the Cure Doce were left. It may well be that they fortified their cities against our artillery-that's why there's pictures of our engines in the book, and details of how they work and what damage they can do." He thought for a moment, then went on: "In which case it stands to reason that either they didn't do what it says in the book, or they didn't do it well enough, or the book's just plain wrong. I guess you'd have to go out with a sextant and a ream of drawing paper and find the shapes in the grass where the old cities used to be. But we haven't got time for that, obviously." He looked up and saw that Catorzes was fidgeting. It's embarrassing, listening to your superiors talking drivel. "See if you can find those maps," he said. "And ask the Architects' if they can send me someone who knows about building walls."
A look of panic flickered in Catorzes' eyes, and Psellus felt a pang of sympathy. How would he have liked it, when he'd been a clerk, if his master had given him an order like that? "Excuse me," Catorzes said slowly, "but they'll want a bit more than that. I mean, building walls is what they all do, surely…"
"Building walls quickly."
He could sense the relief, verging on joy, that the clerk felt as he finally escaped. He envied it. More than anything in the world, he wanted to change places with him. Perhaps he could trick him-lure him into the office, slam the door, lock it and run away, leaving poor Catorzes to rule the Republic. That wouldn't work, of course.
Nine days. The Cure Doce ambassador was a small, wiry man with short white hair, enormous hands and a nose like a wedge. As soon as Psellus walked into the room he jumped up, as though the door was a sear that tripped the catch that held him in his seat. He spoke in snips, like a man cutting foil.
"Thank you for seeing me on such short notice," he said. "Time, obviously…"