Beyond the castle's outer wall.
The banks of the Sázava River, which cut across the Šternberk domain.
This place, ordinarily where the women did their washing and threw out their refuse, now resembled an enormous construction site.
The men hauled logs, and the women carried earth and stone. Even the children did their share, gathering and carrying small stones.
At the center of that worksite rose a structure of bizarre form that had as yet only its framework.
Enormous beyond any comparison with an ordinary hearth or kiln, and shaped with a belly bulging out like a jar.
In the middle of the worksite, Jakub the carpenter was shouting as he raised the skeleton of the enormous structure.
"There, it is out of level! Pull the rope tighter!"
"You are working hard, Jakub."
"Oh, my lord!"
Spotting me, Jakub wiped the sweat from his forehead and came running. His face was steeped in exhaustion, but his eyes shone with energy.
"You have come. As you can see, the foundation frame is nearly all up."
"Yes, faster than I expected. Are you not short of materials?"
"For now it is all right. Only... to support something this enormous, it seems we will need a great deal more thick, sturdy timber and stone. What we have now is nowhere near enough."
I nodded.
The blast furnace now being raised stood at a height well over half that of the castle wall. For that enormous structure to hold molten iron and endure, the foundation mattered more than anything.
"Manpower and materials will be provided in full. Pay no mind to anything else and devote yourself solely to completing the blast furnace."
"Understood, my lord! Just leave it to me!"
I clapped Jakub on the back and headed next for where Pavel the potter was.
Near Pavel's worksite, snow-white bricks were stacked in a mountain.
"Pavel, have you fired enough bricks?"
"Yes, my lord. I fired them at a far higher temperature than ordinary clay just as you said, and rather than cracking, the bricks became hard as stone. Rap them with your hand and they nearly ring like iron."
Firebricks made of kaolin. Without these, the blast furnace would have melted itself down before it ever melted any iron.
"But it truly is a remarkable earth. It is as though a blacksmith forged steel rather than clay being fired. Where on earth did my lord obtain such knowledge?"
Pavel's eyes sparkled with curiosity. Instead of answering I smiled faintly. Fortunately Pavel read the room and pried no further.
This unknown technical knowledge was a highly effective tool for establishing my authority. So long as I was not treated as a heretic, at least.
Just then Tomáš the blacksmith came to find me with a thoroughly hardened face.
A shadow hung over his features.
"My lord, there is something I must tell you."
"What is it? Was the coke a success?"
"The coke was... truly remarkable. It burned hotter and longer than charcoal beyond any comparison. But... the bellows are the problem after all."
What Tomáš spoke of was not the blast furnace whose framework Jakub was raising in earnest, but a small experimental furnace built as a temporary trial.
"To maintain the temperature my lord wants, air must be blown in without a moment's pause, and this is not something that can be done by human strength. Manpower will not come close."
"Hmm...."
Even with three bellows connected to that small firebox, six men had collapsed from exhaustion before the target temperature was reached.
'As expected. We have run into the problem I anticipated.'
What I meant to build was not quite a modern industrial blast furnace, but a thing with productive capacity approaching it.
With the manual bellows of this era the limit was clear. It was only natural that human strength alone could not produce continuous, powerful air.
"We will have to build a waterwheel after all."
"A waterwheel, you say?"
Tomáš immediately wore a troubled expression.
"My lord, forgive my presumption, but that will be difficult. The Sázava River that crosses our domain is narrow and its current is weak. The broad Vltava that runs through Prague might be another matter, but the force of a small stream like this will not come close to turning a waterwheel. A small wheel like the ones used at a mill, perhaps, but..."
Tomáš's words were sound. The river flowing before Šternberk was in truth closer to a brook.
There was no trouble doing laundry or drawing drinking water from it, but the flow was hopelessly insufficient to turn a waterwheel.
"You are right. With a method that uses only the flow of the river it would not come close. Everyone, gather here."
I summoned all the technical officers, drew a parchment from my coat, and spread it out on a flat rock by the riverbank.
The three technical officers held their breath without meaning to and fixed their eyes on my fingertips. An anticipation of what miracle would be drawn this time hovered in their eyes.
On the parchment I drew an enormous wheel with charcoal. But that wheel was not in a form submerged in the river. Instead, a long channel extending above it was connected to the top of the wheel.
"What is this, my lord?"
"We will build a dam upstream, and there we will build a channel connecting to the waterwheel so that the water falls onto the head of the wheel."
"Yes? Onto the top of the wheel?"
"Yes. The force of a weak current pushing the wheel, and the force of water filling dozens of buckets pouring down from above and bearing the wheel down. Which do you think is stronger?"
In that moment Jakub's eyes snapped open. As a carpenter, he was the first to grasp the principle of the design.
"It uses the weight of the water rather than its flow! That is why you told us from the start to set up by the riverbank! And we simply thought it was a convenient place for using water...!"
I curled up the corner of my mouth in a grin.
"It is not over yet. The same goes for the bellows. Producing air only on the push is throwing away half the effort."
Next, on another part of the parchment, I drew a strange device with two boxes joined side by side.
"Look at this device. Connect the shaft in the center, and when you push the board, air comes out of one box, and when you pull it, air comes out of the box on the other side. I have decided to call this a 'double-acting bellows'."
When the explanation ended, this time a stifled groan burst from Tomáš's mouth. He was a blacksmith. He knew in his body, from a lifetime of it, that what determined the strength of a fire was the force of the air.
Powerful air that never broke off for a single moment. If that were realized, then perhaps a flame that could truly melt lumps of iron could be raised.
"If it goes exactly as this design says... we may truly be able to melt iron like water, my lord!"
I laid a hand on Tomáš's shoulder.
"It is not that we may. It will certainly be so."
"Ohh...!"
The faces of the technical officers who had received the designs flushed red with excitement. They put their heads together and began a heated debate.
'This part goes like this...'
'No, the angle of this shaft...'
The worksite, which had faltered for a moment, was filled instantly with a fierce energy. It seemed the completion of the blast furnace was not far off.
Watching the technical officers run off to their own sectors with the designs in hand, I looked up once more at the framework of the blast furnace.
'This is only the beginning. Once we have steel, the next thing is....'
In my head a blueprint for the next stage was already being drawn.
It was not common weapons or armor. It was the beginning of an enormous change that would transform the productive power of this land itself.
Just then János approached carefully and asked.
"My lord, is it really all right to be doing this?"
"Why, what is the problem now?"
"Why, my lord's new toy over there, obviously!"
What János pointed at were the sweating laborers and the blast furnace whose framework had only just begun to go up.
"The Hussite bastards who got back alive from the last battle will certainly have reported every detail to their main force. How their comrades burned to death, and how their prized wagenburg was turned to ashes! And with that being so, is it all right to be playing in the dirt this leisurely?"
"Playing in the dirt, he says. This is a great technological advance for humanity."
"And before that great technology is finished, the Hussite bastards are going to hang our necks first!"
An impatience he could not hide colored his voice.
"They must certainly be sharpening their blades for revenge.... Would it not be better to make more firebombs, or build the wall higher, or at the very least sharpen the soldiers' spearpoints one more time?"
"Hmm...."
It was an entirely sensible and sound concern. I did not think the Hussite bastards would withdraw at this either.
An army led by a peerless hero like Jan Žižka would hardly accept a defeat suffered at a small castle on the frontier like this.
By now a second punitive force on a scale beyond any comparison with the last might well already be forming.
I clapped János lightly on the shoulder.
"You are right. The Hussites will certainly attack again. In greater numbers than last time, and more thoroughly prepared."
"Then how can you be so at ease knowing that!"
János thumped his chest as if in frustration.
"Enough, lower your voice. Everyone is looking. You are making people anxious."
"..."
At my remark János shut his mouth tight. Just as I had said, the people of the domain, who had been working hard, were all pricking up their ears in our direction.
'As I thought, even if they say nothing, they must all be anxious. Winning once is no guarantee of winning from here on.'
I took János with me and walked to a riverbank a little away from the noisy worksite. Looking at the water flowing placidly, I spoke quietly.
"János, what do you think the finest victory in war is?"
"Yes? Well... would it not be winning after fighting only once? As we did last time."
"Wrong."
I shook my head firmly.
"Fighting a hundred times and winning a hundred times is not the best. Winning without fighting at all is the finest victory."
"Winning without fighting? Where is there such a pie-in-the-sky notion?"
János snorted. Chuckling at the reaction, I calmly went on.
"It is not pie in the sky. I have already sent a letter."
"A letter? Have you requested support from His Majesty Sigismund again? He will only toss us a few coins again anyway."
"No."
I drew my gaze back from the flowing water and looked straight at János.
"This time I sent a letter to the Hussites."
"...What?"
János's eyes went round. Like a man who had just heard the most preposterous thing in the world.
"You... you sent a letter to the very bastards who ran away after taking a thunderbolt of fire? No, with what in mind! Surely you did not write something like 'I went a bit far, so let us pretend it never happened and get along from now on'?"
"Of course not."
As if enjoying his snippy reaction, I went on at my leisure.
"János, you seem to think the Hussites are one enormous army, but the reality is different. They are like a snake with two heads."
"Yes? A snake with two heads?"
"One is the Tábor radicals, who would seize the Church's property and drag down the nobles as well. And the other is the moderate nobles of Prague, who would keep the existing order but become independent of the king and the Curia."
The story I had heard from Zdeněk in that old pub, and the fragments of history I had learned in the modern world, drew a clear picture in my head.
Historically as well, it was not an external enemy that brought down the Hussites. What finished them was self-destruction through internal division.
"They are barely held together by the single cause of being the army of God, but they have a fatal weakness. They have no center of gravity."
"Is there not one? The one-eyed man, Jan Žižka. The soldiers wet themselves at the mere sound of his name."
"Žižka is a great commander. But he is not a leader. Fighting well alone cannot win everyone's support. Bluntly, it is not as though Žižka could become King of Bohemia, is it?"
I laughed a little.
"They are no different from a powder magazine that could go off at any moment. The moderates want a kingdom, and the radicals want heaven. They are dreaming different dreams. What do you suppose happens if we throw a spark that no one can ignore onto the fuse of that magazine? So that they blow up among themselves without even the leisure to turn their blades on us."
"Yes? Is such a thing possible? How?"
"Possible indeed."
With a thin smile, I whispered low.
"Because I made them an offer they absolutely cannot refuse."