Stopping with a crash against a padded beam, the entire weighted frame jumped from the ground. The sling whirled round far faster than Shef’s self-designed stone-throwers. Like a streak the rock flashed across the minster-yard, never rising—not lobbed but hurled. The straw target billowed into the air, slowly collapsed on its slings. The slaves cheered once in triumph.

Slowly Ivar turned to Erkenbert. “That is not it,” he said. “The machines that rained death on my army, they threw high in the sky.” He lobbed a pebble upward. “Not like this.” He hurled another at a pecking sparrow.

“You have made the wrong machine.”

“Impossible,” said Erkenbert. “There is the great machine for sieges. And this one for men. None other is described in Vegetius.”

“Then those bastards of the Way have made a new thing. One not described in—in your book.”

Erkenbert shrugged his shoulders, unconvinced. Who cared what this pirate said? He could not even read, still less read Latin.

“And how fast does it shoot?” Ivar glared at the slaves twirling their levers. “I tell you, I saw the stone-throwers hurl another while the first was still in the air. This one is too slow.”

“But it strikes hard. No man can resist it.”

Ivar stared thoughtfully at the fallen target. Suddenly he whirled, yelled orders in Norse. Hamal and a handful of companions sprang forward, pushed the slaves out of the way, and heaved the cumbrous, tense-wound machine round.

“No,” shouted Erkenbert, pushing forward. Ivar’s arm clamped irresistibly round his throat, a wire-muscled hand forced his mouth shut.

Ivar’s men pushed the machine round another foot, hauled it back a trifle as their leader ordered. One hand still effortlessly holding the limp deacon off the ground, Ivar jerked the string a third time.

The giant door of the minster—oak beams nailed across each other in double-ply, held fast over all with iron bands-exploded in all directions, splinters flying in slow arcs across the yard. From inside came a chorus of wails, monks leaping out, darting back, shrieking in terror.

They all stared in fascination at the great hole the boulder had smashed.

“You see,” said Erkenbert. “This is the true stone-thrower. It strikes hard. No man can resist it.”

Ivar turned, eyes fixed on the little monk in contempt. “It is not the true stone-thrower. There is another kind in the world of which you know nothing. But strike hard it does. You must make me many.”