Two hours after the sun had set behind the mountains and darkness has filled the valley, Napoleon and Berthier stood on a small spur of rock to watch the assault.An infantry battalion, with several ladders, was already picking its way up the road from the village. Each man was carrying only his musket and a cartridge pouch, although none of their weapons was loaded yet, in case some fool fired by accident and alerted the garrison. Down in the village, a column of supply wagons and a battery of limbered guns were ready to move forward the moment the attack began. Once night had fallen, engineers had crept down the road, smothering it with straw and dung to muffle the sound of the vehicles’ wheels, which had been wrapped in sacking.

A blazing wicker bundle suddenly flared up on the gatehouse of the fort and then it arced out across the road, landed in a shower of sparks and began to roll down the slope, illuminating the attackers as they dived aside to avoid being mown down by the flaming ball. At once the Austrian guns blasted a storm of grapeshot into the ranks of the French infantry racing towards the walls with their spindly-looking ladders. As Napoleon watched, scores of his men were struck down by the withering fire from the fortress and only a small party reached the outermost bastion and threw their ladder up against the wall. But they died to a man in the crossfire from the other squat towers that projected from the wall.

Napoleon turned his attention to the road that passed down the ravine.The column there had been ordered to move forward the moment the firing began. It was too dark to trace their progress amid the snow-laden trees that ran beside the track, and Napoleon nodded his satisfaction with that. If the Austrians missed them, then Lannes would have enough artillery to continue his advance. But even as the thought passed through his mind, more flaring bundles tumbled down from the fortress and the startled men driving the wagons and gun carriages were lit up in the red glow the flames cast across the gleaming snow on the ground. Tiny stabs of light rippled along the wall as the defenders fired their muskets down into the ravine.

‘At least their guns can’t be trained on the road immediately below the fortress,’ Napoleon commented.

‘They don’t need guns,’ Berthier responded grimly. ‘Look there.’

A spark, like a star, arced down towards the road and a moment later there was a brilliant explosion as a grenade blew up close to one of the gun limbers, dropping all but the lead horses. By some miracle the driver escaped injury and stood up and stared down at his dead and dying horses in their traces.Then he was hit and toppled to one side and lay still on the ground.