There were many prerequisites Bjorn had worked through before attempting the blast furnace—tall, stone-lined furnaces with continuous charcoal feed and slag taps, waterwheels driving blast air hot enough to reach 1500°C for pig iron production.
First came improving the bloomery furnaces: lining them with clay and refractory materials, adding forced air via water-powered bellows for consistent high temperatures. They had to track carbon content carefully to avoid brittle iron.
But even that required prerequisites—basic forging techniques, learning to hammer iron into shapes, quenching in water for hardness, annealing for ductility. And access to rivers for the waterwheels. All already achieved.
Second was developing proper refractory clays: mixing local clays with sand and ash for high-heat resistance, building updraft kilns that could fire evenly up to 1300°C. Better furnace linings meant higher-tier smelting. Each step built on the last.
Most of the winter Bjorn spent near the river workshops, watching clay and ore burn a hundred different ways. He spoke little. The craftsmen had learned to read his silence by now—an approving nod here, a sharp gesture there.
The new furnace rose slowly out of stone and clay, higher than any smith had ever dared build. It looked wrong to them at first, too tall, too narrow. Smiths trusted what they knew: squat furnaces, close to the ground, hot enough for bloom, nothing more.
Bjorn said nothing of "invention" or "new age." He spoke only of trying something different and better. No one argued with him anymore, even if they knew better than him in their respecting field. If you did you were an idiot, and no one wanted to look the idiot in front of his peer.
When the snows softened and the river began moving again, they set the waterwheel turning. The bellows groaned like an animal, forcing air up the tall furnace day and night. It was not quick work. Sometimes the heat failed. Once the lining cracked and half the wall had to be rebuilt.
On the day they opened the lower tap, most men stood back—expecting only another bloom, another spongy mass wrapped in slag. The master smith stepped closest, because he always did.
His beard was stiff with charcoal dust. When the front finally broke open, something heavy slid forward—darker, smoother, a single piece, not breaking apart like every iron they'd ever seen.
The sound in the workshop died.
Ragnar was here, leaning against the timber post at the edge of the workshop. He said nothing. Only watched, his eyebrows rose from time to time, but that was it.
Athelstan, further back, was writing on paper, stopping often to observe the waterwheel turning. Bjorn brought him here to record this.
Arnor, the master smith, touched the cooled edge with the head of his hammer, testing its weight without seeming to trust it.
"That's iron. Iron… this is iron?" he said. Not quite sure what he was looking at.
Bjorn crouched beside him. The surface held the shape of the furnace wall, melted against it like metal poured in one piece.
"Yes it is. And it came out whole. That means we succeeded. Great success." Bjorn said in triumph.
Ketil, old enough to grow a beard, and to apprentice here, lifted a smaller fragment with a tool, grunting at the weight. "By the gods, It feels… thicker inside than usual," he murmured. "Can i strike it? Let me do it to see how it holds."
Arnor didn't answer. He was staring at the metal like it owed him silver and gold and goats, jaw working side to side. Finally he breathed out through his nose, long and slow, and Bjorn knew that sound. That was the sound of a man realizing the thing he'd spent his whole life doing might not matter anymore.
"Why's it smooth?" someone called from the back. "Where's all the slag?"
"The iron rose while the slag sank beneath it," Bjorn said, nodding toward the dark flow at the tap.
"But Iron doesn't go up," Arnor said. Bjorn could tell he wasn't arguing, just stating facts.
"This one did."
"Too much heat ruins it." That was Halvard, thick-shouldered, thick-headed. "Everyone knows you burn the strength out if you go too hot."
"Everyone's wrong sometimes." Ketil was still holding his chunk, turning it in the light.
Halvard's face went red. "Watch your mouth, boy."
"I'm just saying what we're all—"
"You're saying nothing worth hearing."
"Enough." Arnor's voice stopped them from embarrassing themselves further in front of the King. Both men shut up. He squatted down next to Bjorn, knees cracking loud enough to hear across the room. Studied the metal. Glanced at Bjorn, back to the metal. "If it melts all the way through like this, it'll be brittle and maybe shatter when you try to work it. Like glass."
"Go ahead then. Hit it and let us know." Bjorn responded.
Arnor picked up his hammer. His hand shook just a little, but Bjorn saw it. The master smith raised it, hesitated, actually hesitated, then brought it down.
The ring echoed off stone walls.
The metal didn't shatter. Didn't crack. A dent. Small. The metal held.
Arnor hit it again, harder. A chip flew off. The rest stayed solid, dense in a way bloom never was. He lowered the hammer slowly, staring at it like it had betrayed him. His lips moved but nothing came out at first.
"This isn't bloom," he finally said, almost to himself.
Ketil was grinning now, couldn't help himself. "It's heavier, right? That means stronger?"
"Means more brittle, only the gods can be sure," Halvard said, but he was moving closer despite himself, unable to stay back. "Let me see that."
Ketil handed it over. Halvard tested the weight. His face did something complicated—confusion, anger, fear, all at once. "If this thing does all the work," he said, and his voice had gone quiet, dangerous, "what in the gods' name will smiths do?"
Silence reigned over the smiths as the words of Halvard brought them to their present.
"You will be doing the same work. Just more of it." Bjorn reassured them. And he wasn't sure if that made them satisfied or not.
Athelstan looked up from his parchment, ink wet on the page. "What are you calling it?"
All eyes turned towards Bjorn, "Well since it's a new kind of iron. Let's call it the King's iron. Write that down, Athelstan. You did? Good. Wait, i changed my mind, let's name it Pig Iron." Bjorn finally named it with it's future name after playing with Athelstan a little, making him write the first name, then strike it out and write the second.
Athelstan glanced at him with a look that said, 'Really?'
"Pig Iron?" Ketil asked in confusion.
"Because the iron flows from one main channel into smaller pieces. The big flow is the mother, the smaller pieces are the pigs." Bjorn responded.
Now with this blast furnace, volume jumps dramatically quality improves weapons become cheaper tools become cheaper armor becomes possible in numbers trade value explodes state power increases
Bjorn achieved another Victory and outpaced the world.
So he immediately ordered his men that he wants two furnaces made this year which will multiplie labour and charcoal demand.
The success of the blast furnace made Bjorn realize it was time to expand his huskarls. He issued a royal decree, calling for men between seventeen and thirty to join his warband—though only five hundred would be chosen through an initial test in each Kingdom, then gather the chosen recruits to Kattegat for final training.
They will receive no regular wages, just like the old huskarls. Only the master smiths and the most skilled craftsmen were granted Drottir; the rest lived on what Bjorn provided—shelter for those without a home, food, weapons, and helmets. Many of the huskarls shared longhouses, sleeping and eating under one roof.
When they raided west, their share of the loot became their income. Those who wished to establish a longhouse of their own, start a family, or rise in status contributed a portion of their earnings back to Bjorn's household. Everything was earned through service, skill, and loyalty.
Bjorn received news from the glassmaker he brought from Frankia.
-x-X-x-
Bjorn stood on the cliff overlooking the southern approach to the harbor, where the watchtowers kept their vigil and the great wooden chain waited beneath the waterline. The morning was gray and cold, the kind that sank into your bones and stayed there.
The glassmaker—Matthieu, though most just called him the Frank—stood beside him, nervous and proud in equal measure. He held a wooden case like it contained something sacred.
Bjorn's white hair lifted in the wind, as he signaled the man to start his presentation.
Matthieu opened it carefully, revealing the lens nestled in wool. It was maybe the length of a man's palm, curved and polished until it caught the weak sunlight and bent it strangely.
"My lord," Matthieu said, and his voice carried the careful respect of a foreigner who knew how quickly favor could turn. "As you requested."
Bjorn took it and held it up to his eye.
At first, there was nothing. Just the fjord, gray and empty, stretching to the horizon. Then he adjusted the angle, tilting it slightly downward, and the world shifted.
A cluster of sails appeared, far beyond what he should have been able to see. Dozens of them. Moving steadily toward Kattegat, already past the outer markers.
His own ships, returning from a patrol. But still. The distance.
"It's not bad," Bjorn said, lowering the lens. He turned it over in his hands, examining the edges, the polish, the way light moved through it. "You've done well."
Matthieu's shoulders relaxed slightly.
In truth by Bjorn's standard, It's crude. The magnification, two times? Three at best? Maybe four if the conditions are perfect. And the field of view is bad. Like looking through a keyhole. You'd have to scan constantly to see anything useful.
Bjorn rubbed his thumb across the surface. With rain, sand, win, It'll lose clarity fast.
The glass is delicate. It would need to be cleaned often and Protected.
"But not bad means you can make it better."
The Frank blinked. Then understanding dawned on him.
"Yes, my lord. I can try—"
"Bjorn! Bjorn, let me see! You promised!"
They both turned. Ubbe came running up the path from the hall, all five years of him, barely able to contain himself. Huskarls were by his side, protecting him.
His small furs were already dirty from whatever he'd been doing that morning, and his hair stuck up at odd angles.
Bjorn had called for him specifically for this. Watching distant things grow close—that would seem like magic to a child. And Ubbe needed to understand that what seemed like magic was just craft and patience and understanding how the world worked.
"Alright," Bjorn said, crouching down so they were eye level. "But carefully. And don't drop it."
Ubbe took the lens with both hands, almost reverent, then immediately pressed it against his eye and started swinging his head around wildly, looking at everything and nothing.
"Where is it?" Ubbe frowned, pulling the lens back and squinting at it suspiciously. "You said it makes things close. I don't see anything. Not even you." He pointed it directly at Bjorn's face from two inches away.
Bjorn sighed. "That's because you're using it wrong, Galileo."
"My name is Ubbe."
"I know what your name is." Bjorn took the lens back, held it at the proper distance, showed him the angle. "Watch. You hold it like this, see? Far enough from your eye that the light can reach it properly. Then you adjust until it's clear."
He handed it back. Ubbe tried again, this time following his brother's instructions. He frowned, concentrated, moved it slightly, then—
"Oh!"
His whole face lit up. He swung toward the ground, staring at ants crawling over stone. Then toward the harbor, where the distant ships suddenly seemed close enough to count their rigging. His mouth hung open.
"I can see them," Ubbe breathed. "I can see them like they're right here. Like I'm standing on the ship." He pulled the lens away to verify, looked back through it, then at Bjorn with pure wonder. "How?"
"Since you want to know. The glass bends light," Bjorn said. "Brings it to your eye from farther away than it would normally reach. That's all."
Bjorn was sure Ubbe wasn't even listening.
Ubbe was already scanning again, drunk on the newness of it. Then he stopped, tilted his head back toward the sky. "Can I look at the sun?"
Bjorn's hand shot out, covering Ubbe's eye and snatching the lens away in one motion.
"You can," Bjorn said, and his voice had gone hard. "If you want to burn your eyes out of your head and spend the rest of your life in darkness."
Ubbe froze, suddenly uncertain.
Bjorn held the lens up between them. "Never point this at the sun. Never. The glass focuses light—all of it, more than your eye can handle. It would burn through like fire. Do you understand?"
Ubbe nodded quickly. "Like fire."
"Good." Bjorn straightened, turning back to Matthieu. The Frank had been watching the exchange carefully, like a man who knew better than to comment on how kings raised their brothers.
"One lens is good," Bjorn said, and his tone shifted back to the practical. "But it's not enough. I want you to make another. A second piece of glass, paired with the first."
Matthieu's eyebrows rose. "Another lens, my lord?"
"Yes. One to magnify, one to correct." Bjorn gestured toward the fjord. "With both working together, the magnification will increase dramatically. The field will be clearer. The distance—" He paused, watching those far sails. "—will become truly usable."
Matthieu rubbed his chin, thinking. "Two lenses... One larger, one smaller perhaps? A magnifying piece and a..." He struggled for the word. "A shrinking piece?"
"Exactly." Bjorn's eyes narrowed thoughtfully. "But they have to be aligned. Perfectly. If they shift even slightly, everything blurs and the horizon disappears. So we need something to hold them. Like a tube. Something that keeps them in line and blocks stray light from scattering the image."
"Build it then test different lengths and different positions."
Matthieu frowned, working through the problem in his head. "But my lord, how will I know the correct distance between the lenses? Too far, too close—the image will be useless."
"Trial and error," Bjorn said simply. "There's no formula for this. No one's done it before. You grind, you test, you adjust. One day it works. Then you do it again to make sure it wasn't luck."
Matthieu grinned despite himself, caught between disbelief and excitement. "I've never made anything like this before, my lord."
"Good," Bjorn said. "Neither has anyone else." He clapped the man on the shoulder—a rare gesture of approval that Matthieu would probably repeat to his children someday. "Start today. Grind carefully. Align slowly. When the light passes through both pieces perfectly, we'll know."
Once Bjorn returned to his hall, he sent word to the Jarls. A chance to join him in a new expedition to discover lands beyond the known world.
The message was deliberate. He didn't say "search for" or "seek out" new lands. He said discover. As if he already knew they were there. As if it was only a matter of sailing far enough to reach them.
Let them wonder how he could be so certain. Let them ask each other in low voices whether the white-haired king had spoken to the gods themselves in his sleep.
Mystery was useful. It made everyone uneasy.
Five days later, the inland Jarls arrived for the feast. They came with their retinues, their best furs, their carefully neutral expressions. The hall had been prepared—long tables heavy with roasted meat and fresh bread, ale flowing freely, the fires burning high enough to chase away the spring cold.
Bjorn sat at the high table, Ragnar, Pregnant Lagertha, Rollo and all his family sat close to him, several of his most trusted huskarls stationed along the walls.
The feast began well enough. Toasts were raised. Old stories were told. Men laughed at the appropriate moments, their voices too loud, their smiles too wide. Everyone was performing the ritual of friendship.
It didn't take long for the real business to begin.
A broad shouldered Jarl stepped forward, showing respect in the way he stood.
"My king," he said, and the title still sounded strange in some mouths, like a word they hadn't quite learned to pronounce correctly. "I hear you're expanding the huskarls. Five hundred new men."
"I am," Bjorn said.
"My nephew—my sister's second son—is seventeen. He is strong and eager to prove himself." His smile was practiced. "It would honor our family if you would consider him."
"Send him to the trials," Bjorn said. "If he's strong and eager, he'll have his chance like everyone else."
The man's smile tightened slightly, but he bowed again and withdrew.
Then came another Jarl, offering his younger brother's son. Then another, suggesting his second son might benefit from the discipline of the king's warband. Then another Jarl, presenting his nephew as if the boy were a gift Bjorn should be grateful to receive.
Always nephews and always second sons. But never the heir.
Bjorn understood perfectly. They were afraid of him and of what he represented.
Centralized power. Royal authority that didn't stop at the borders of Kattegat proper but reached into their halls, their lands, their families.
They still held autonomy, technically. Their people still answered to them first. But everyone knew how fragile that autonomy was becoming. How quickly it could become ceremonial rather than real.
And if your heir trained under Bjorn, if your heir's loyalty was shaped by years at the king's side, learning the king's ways, adopting the king's values—then what did your autonomy matter? You became disposable. Your heir became the new Jarl when Bjorn decided you were no longer useful. And your independence became theater.
The huskarls were loyal to Bjorn. Only Bjorn. Everyone knew that. It was the entire point.
So they offered their expendable sons and hoped it would be enough and keep them safe without risking everything.
All of them did this.
Except one.
Jarl Runi rose from his seat near the middle of the hall. He wasn't the richest Jarl, nor the one with the most warriors. His lands were decent just like the rest.
He moved forward with a boy at his side, no older than thirteen. He was tall for his age, with his father's dark hair and a nervous energy he was trying hard to suppress. The boy's eyes darted around the hall, taking everything in—the huskarls, the king, the other Jarls watching with sudden interest.
Runi stopped at the appropriate distance and bowed. When he straightened, his expression was calm, almost pleasant.
"This is my oldest son," Runi said, his voice carrying clearly through the hall. "My heir. Vidar." He placed a hand on the boy's shoulder. "I wish for you to accept him with his huskarls, King Bjorn. To train with your new warband. I believe he would learn best from you."
The hall went quiet. Not the comfortable quiet of men eating and drinking, but the sudden quiet of wolves catching an unfamiliar scent.
Bjorn set down his cup carefully. He studied Runi for a long moment—the man's posture, the steadiness of his gaze, the way he kept his hand on his son's shoulder like it was the most natural thing in the world.
Bold and politically savvy, yet not suicidal.
Which meant Runi wasn't doing this out of blind obedience. He wasn't throwing his son away in some desperate attempt to curry favor. He was making a calculated move.
Bjorn thought. 'Hmmmmmmmmmmmmmmmm'
This wasn't about serving Bjorn directly. It was about positioning himself cleverly within the new order that was coming whether the Jarls liked it or not. By offering his heir, Runi was signaling something: 'I see where this is going. I'm not going to fight it. I'm going to adapt and profit from it.'
He was betting that having his son close to the king—truly close, not just as a disposable nephew or second son—would give him more influence than the fragile autonomy the other Jarls were clinging to. He was accepting the reality of centralized power and trying to secure a place within it.
"Your son," Bjorn said finally. He looked at the boy—Vidar—who was trying very hard to stand straight and look worthy of attention. "How old are you?"
"Twelve, my lord." The boy's voice cracked slightly on the last word. He flushed but didn't look away.
Bjorn stood, descended from the high table, and walked closer. The boy tensed but held his ground. Good. Fear was acceptable. Cowardice wasn't.
"Your son will train among my warriors," Bjorn said, speaking to Runi but keeping his eyes on Vidar. "He'll take no greater share of comfort than they do. No less hardship either." He paused, letting the weight of that settle. "If he proves himself—if he shows courage, and good judgment when fear comes for him, then in time, I may choose him as a shield-bearer."
The words were careful and polite on the surface.
But the hall heard what he wasn't saying: Your son gets nothing for free. Not because of who his father is. Not because of blood or land or inheritance. He earns his place or he fails.
"I reward strength and loyalty when I see it," Bjorn added, his tone light, almost conversational. "Those who rise highest beside me will be the ones who've earned their place."
He turned slightly, just enough to include the other Jarls in his peripheral vision.
"All of them."
The surface sounded fair and honorable. But every Jarl heard the deeper meaning from the way their faces changed: Bjorn was building a future around those loyal to him alone, chosen by his own hand, not by birth. No one—heirs included—would enjoy privilege simply because of lineage.
Runi bowed again, deeper this time. "Thank you, my king. He will not disappoint you."
Bjorn nodded once and returned to his seat. The moment passed. Conversation resumed, though it had a different texture now; more cautious, more thoughtful.
The other Jarls were recalculating. Some looked at Runi with barely concealed envy. Others with suspicion. A few with contempt for what they probably saw as weakness, surrendering his heir to the king's influence.
But Runi just sat down, poured himself more ale, and looked entirely satisfied with himself.
'He should be,' Bjorn thought. He'd just bought himself a stake in the future while the others were still trying to cling to the past.
At last, the time to sail came. The hall emptied, but the echoes of today's choices lingered in every mind.
Caution preserves their lives; foresight may elevate their line. Vidar is the example.