Ragnar stood on the beach, looking at the Saxon corpses being stripped of their armor by the efficient Viking scavengers. He looked at the dead horse he had crushed with the trebuchet arm. It was a gruesome sight, but his engineer's brain was focusing on the method.
I got lucky, Ragnar thought, rubbing his shoulder. If that rope hadn't snapped just right, or if the horse had been two seconds faster, I'd be a shish kebab on a Saxon lance right now.
He looked at his hands.
"I need an equalizer," he muttered.
He walked over to the trebuchet he had built. He stared at the massive ropes that held the throwing arm. They worked on tension and gravity. But the Romans had used something else for their ballistas: Torsion. Twisted bundles of rope or sinew that stored immense energy.
Ragnar kicked a broken Saxon spear lying in the sand. The shaft was snapped, leaving only the iron tip and a foot of wood.
A spear, he mused. The king of weapons. Reach, penetration, simplicity.
But a spear required muscle. You had to thrust it. You had to have the momentum.
What if the spear thrusts itself?
In the fantasy novels and games he used to play in the 21st century, there was often a weapon called a "Torsion Spear" or a "Pile Bunker." A massive, pneumatic spike that punched through dragon scales.
But that's fantasy, Ragnar corrected himself. If I built a full-sized torsion spear that could punch through a shield, Newton's Third Law would break my arm. The recoil would be equal to the impact. I'd fly backward as fast as the enemy flew forward.
He picked up the broken spear tip.
But what if I don't make it big? What if I make it... compact?
He imagined a tube. Inside the tube, a spike. Behind the spike, a tightly twisted bundle of animal sinew the strongest natural spring available in 865 AD. A trigger to release the tension. It would be a "get off me" button.
"Bjorn!" Ragnar shouted.
Bjorn was currently trying to teach a crab how to fight a rock. He looked up, bored. "Yes, Logistics Master?"
"Bring me the cow guts," Ragnar said with a manic glint in his eye. "And find the smith. We're making a toy."
The camp smith, a burly man named Leif (not to be confused with the other three Leifs in the army), looked at Ragnar's drawing in the sand.
"You want a tube," Leif summarized. "Made of iron. Closed at one end. Open at the other."
"Yes," Ragnar said. "And I need a steel spike that fits inside it perfectly. Not too tight, not too loose. Like a piston."
"Piston?" Leif scratched his beard with a hammer. "Is that a type of fish?"
"Just make the spike, Leif," Ragnar said, too excited to explain internal combustion terminology. "And I need a catch. A little lever here." He pointed to the side of the tube. "When I press it, the spike flies out."
"And what pushes it?" Leif asked.
Ragnar held up a bundle of dried, twisted intestines he had scavenged from the butchers. "This."
Bjorn, who was watching over Ragnar's shoulder, looked skeptical. "You are going to fight the English with cow guts inside a pipe? Ragnar, maybe the sun has boiled your brain."
"It's called torsion, brother," Ragnar said, kneeling to twist the prototype bundle. "When you twist the fibers, they want to untwist. They store energy. If we twist them tight enough, they release that energy faster than your arm can move."
"If you say so," Bjorn shrugged. "But if it explodes, I get your boots."
It took all afternoon. The army was resting, eating, and preparing for the march to York, which gave Ragnar the precious time he needed.
Leif forged the tube from a section of a broken anchor shaft. Ragnar spent hours carefully winding the sinew. He used a small winch to twist the fibers tighter and tighter until they hummed with tension.
He loaded the spike into the tube, pushing it back against the twisted sinew until it clicked into the crude trigger mechanism Leif had fashioned.
The result was a heavy iron cylinder, about the length of his forearm. It looked like a very primitive, very angry flashlight.
"It is ugly," Bjorn decided, inspecting the device.
"It's a prototype," Ragnar defended. "The Torsion Spike Mark I."
"Mark One?" Bjorn asked. "Who is Mark?"
"Never mind," Ragnar stood up. "Let's test it."
They walked to the edge of the camp, away from the crowds. Ragnar set up an old, cracked wooden shield against a tree. It was a sturdy piece of linden wood, covered in leather the standard protection for a Saxon warrior.
"Okay," Ragnar said, taking a deep breath.
He strapped the device to his right forearm using leather belts. It felt heavy, but reassuring. The iron tube ran along the underside of his arm, the tip just barely protruding past his wrist. The trigger was a small loop he held in his hand.
"Hit the shield," Bjorn said, crossing his arms. "I want to see it bounce off."
Ragnar stepped up to the tree. He stood about a foot away from the shield.
This is it, he thought. Close quarters combat. No room to swing a sword. Just a punch.
He made a fist. He visualized the physics. The sinew would unwind violently, driving the piston forward. The recoil would shoot back into his arm, but because the mass of the spike was small compared to his body weight, he should be able to absorb it if he locked his stance.
"Hello, Saxon," Ragnar whispered to the tree.
He punched forward, pulling the trigger loop at the exact moment of impact.
The sound was sharp, like a hammer hitting a coffin.
Ragnar gasped, stumbling back two steps. His arm felt like he had just punched a brick wall. The recoil had jarred his elbow, sending a shockwave up to his shoulder.
"Odin's beard!" Bjorn shouted, running to the tree.
Ragnar shook his numb arm and joined him.
There, embedded in the shield, was the spike. It had punched clean through the wood, through the leather, and buried itself two inches into the oak tree behind it. The shield was pinned to the tree!
"It went through," Bjorn whispered, his eyes wide. He touched the iron tube on Ragnar's arm. "No swing? No axe wind-up? Just... pop?"
"Just pop," Ragnar grinned, ignoring the pain in his wrist. "It's a hidden fang, Bjorn. A warrior raises his shield to block my sword. I step in close. I punch his shield. This goes through the shield and into his chest."
Bjorn looked at the device with a newfound reverence. He looked at the hole in the shield.
"Can you make a big one?" Bjorn asked, drooling slightly. "Like... a spear size?"
"No," Ragnar said firmly, unbuckling the straps. "If I made this spear-sized, the recoil would have dislocated my shoulder and probably thrown me into the sea. This works because it's small. It relies on speed, not mass."
He reloaded the device. It took some effort but it was doable.
"It's a one-shot weapon," Ragnar explained. "I use it to survive a surprise attack. Then I run away or use my dagger."
"I want one," Bjorn demanded.
"You have an axe that weighs as much as a small child," Ragnar pointed out. "You don't need this."
"I want two," Bjorn corrected. "One for each arm."
Ragnar laughed. "Let me refine the trigger first. I nearly broke my finger."
As the sun began to set, painting the English sky in bruised purples and bloody oranges, Ragnar sat by the fire, tinkering with the Torsion Spike. He was polishing the internal track with some animal fat to reduce friction. He felt eyes on him.
He looked up. Princess Gyda was standing there, her white fur cloak glowing in the firelight.
"The men say you punched a hole through a tree," she said. Her voice was calm, but her eyes held that same dangerous curiosity from the boat.
"It was a shield. And the tree was behind it."
Gyda sat down on the log opposite him. She didn't care about the dirt on her fine dress.
"Show me," she commanded.
Ragnar held up the device. "It uses twisted sinew. Like the big machines, but smaller."
"Stored force," she nodded, recognizing the principle. "Like a bow, but contained."
She reached out and touched the cold iron. Her fingers were long and slender, contrasting with the crude, brutal metal.
"My father thinks you are a coward," Gyda said casually. "He thinks fighting from a distance is weak."
"And what do you think, Princess?" Ragnar asked, tensing slightly.
"I think," she said, looking him in the eyes, "that a dead hero is useless. And I think you are the most dangerous man in this army because you don't play by their rules."
"Make one for me," she said.
Ragnar blinked. "You? But you... you stay in the tent."
"Do I?" Gyda raised an eyebrow. "If the camp is overrun, do you think the Saxons will care if I am a princess?"
She pointed to the device.
"But this? This requires no strength. Just a steady hand and a clever mind."
Ragnar looked at her. She was right. In this world, being a woman often meant being a target. A weapon that leveled the playing field was exactly what she needed.
"It has a kick," Ragnar warned. "It hurts the arm."
"I can handle pain," Gyda said softly. "I cannot handle being helpless."
Ragnar nodded slowly. "I'll make you one. Smaller. Lighter. We'll use bronze for the tube so it doesn't rust, and I'll pad the arm brace with wool."
Gyda stood up. She looked at the trebuchets towering in the distance, then back at the small iron tube.
"We march for York tomorrow," she said. "The walls are high. The Saxons are waiting."
"We're bringing the future to their doorstep." Ragnar said, strapping his invention back onto his arm.