Round the carts there clustered a mob of thralls, the runaways of the region, each catapult crew stepping by its cart and its machine, each crew captained by one of Shef’s original dozen. The Vikings did not like this. Yes, every army needed a gang of thralls to dig latrines, light fires, groom horses. But gangs this size? All eating their share of the supplies? And starting to think they might not be thralls after all? Even the followers of the Way had never considered admitting men who did not speak Norse to full fellowship. Nor did Shef dare to suggest it.

He had made clear to Padda and the rest of the machine-captains that they had better tell their men to keep their heads down. “If someone wants you to grind his meal or pitch his tent, just do it,” he had told them. “Otherwise keep out of the way.”

Yet he wanted his recruits to feel different. To take pride in the speed and dexterity with which they leapt to their places, turned the levers or whirled the beams.

To mark them out, every catapult-man now wore an identical jerkin, made only of rough sackcloth, hodden gray, over the rags they had been wearing when they arrived. On it each man had carefully stitched a white linen double-headed hammer, front and back. Each man, too, had a belt or at least a rope round his middle, and all those who owned them bore knives.

Maybe it would work, thought Shef, watching the carts creak forward, Vikings in front and behind, jerkined freedmen in the middle. Certainly they were much better already with the catapults than the Vikings they had replaced. And even on a winter day in the raw cold, they looked cheerful.

A strange noise split the sky. At the front of the train of carts, Cwicca, a thrall who had come in a few days before, escaped from the shrine of St. Guthlac at Crowland, had brought with him his treasured bagpipe. Now he led the carts along, cheeks puffed, fingers skipping briskly on the bone pipe. His mates cheered and stepped out harder, some of them whistling in unison.

A Viking from the vanguard turned his horse, scowling angrily, front teeth sticking out. It was Hjörvarth Sigvarthsson, Shef saw. His half brother. Sigvarth had volunteered instantly to join the expedition with all his crews, too quickly to be turned down, quicker even than Thorvin or the Hebrideans or the still-doubting Brand. Now Hjörvarth trotted back menacingly towards the piper, sword half-drawn. The music wailed discordantly and died.

Shef turned his pony between them, slipped off it and handed the reins to Padda.

“Walking keeps you warm,” he said to Hjörvarth, staring up at the angry face. “Music makes the miles go faster. Let him play.”