On a day of sunshine, when the martins were busy making their nests in the old masonry of Burgos Castle, Major Pierre Ducos stared down from the ramparts.

He was hatless. The small west wind lifted his black hair as he stared into the castle’s courtyard. He fidgeted with the earpieces of his spectacles, wincing as the curved wire chafed his sore skin.

Six wagons were being dragged over the cobbles. The wagons were huge, lumbering fourgons, each pulled by eight oxen. Tarpaulins covered their loads, tarpaulins roped down and bulging with cargo. The tired oxen were prodded to the far end of the courtyard where the wagons, with much shouting and effort, were parked against the keep’s wall.

The wagons had an escort of cavalrymen who carried bright-bladed lances from which hung red and white pennants.

The garrison of the castle watched the wagons arrive. Above their heads, at the top of the keep, the tricolour of France flapped sullenly in the wind. The sentries stared out across the wide countryside, wondering whether the war would once again lap against this old Spanish fortress that guarded the Great Road from Paris to Madrid.

There was a rattle of hooves in the gateway and Pierre Ducos saw a bright, gleaming carriage come bursting into the courtyard. It was drawn by four white horses that were harnessed to the splinter-bar with silver trace chains. The carriage was driven too fast, but that, Ducos decided, was typical of the carriage’s owner.

She was known in Spain as La Puta Dorada, ‘the Golden Whore’.

Beside the carriage, where it stopped beneath Ducos’ gaze, was a General of cavalry. He was a youngish man, the very image of a French hero, whose gaudy uniform was stiffened to carry the weight of his medals. He leaped from his horse, waved the coachmen aside, and opened the carriage door and let down the steps with a flourish. He bowed.