And now, shaking itself to life with a series of crashing explosions, here came the most spectacular machine of all. It was the testudo, named by the brothers after the famous formation of the Roman legions. It was a great shell of steel, immensely heavy, tough enough to withstand a direct hit from any of the defenders’ petty weapons. Cannon fired from ports in all the forward angles, and as it advanced it shook and shuddered, smoke billowing from its ports from the internal detonations that drove it forward. It was unstoppable, inhuman. The testudo simply crushed a crumbling stone wall beneath its great hidden wheels, and the defenders, their shot and bolts and arrows simply bouncing off the mighty shell, fled, probably terrified out of their wits by the noise alone.

From James’s elevated vantage he could smell nothing of the battle; he could hear little save the distant crump of explosions and the shouting of men like birds’ cries, sounds drowned by the hiss of the wind in his wings, and his own rapid breathing. It was like watching a battle played out with toys, he thought - distant and abstract enough to quash his own conscience, and to allow him to savour the exhilaration of his extraordinary flight over these engines of carnage.

Now it was time for James himself to deliver the finishing blow. He tugged on guide ropes so that his wooden bird swooped to a line that led straight to the mock fortress. He glanced to his left to the observers’ canvas pavilion, to see if Bartolomeo Colon and the rest were watching him. He saw Grace in a bright purple gown. He grinned, and the wind was cold on his teeth, and his heart beat even faster.

He banked over the fortress. As his huge shadow crossed the village some of the defenders ran, their superstitious fear overwhelming them, though they knew it was James. Now he pulled at the leather tags at his belt, one, two, three, four. The metal eggs were released and fell straight down, their bird-like shapes cutting through the air, the fins at their backs stabilising their fall.

All four landed in the heart of the fortress, splashing fire as they hit. The noise of the explosions reached him, and a sudden updraught of hot air pushed him higher. He whooped with an unreasonable joy. James was a man of peace, but he was young enough to relish the sheer exhilaration of such a complicated and dangerous game.

And as the fires bloomed he thought of Grace, Grace pushed down before him, Grace begging for his forgiveness - begging him to stop.

He looked over at the pavilion. Grace and the others were standing and pointing - not towards James and the fortress, but east. James craned his neck to see that way.

Something was wrong.

XVIII

XVIII

‘The testudo,’ Ferron said weakly, ‘is astounding. Devilish!’