A signal gun fired from the Austrian forces massed to the west and, an instant later, the batteries formed up in front of the infantry spat tongues of flame and were instantly swallowed up in a bank of smoke. A moment later the sound of the discharge rolled across the battlefield like thunder as roundshot carved bloody paths through the ranks of Victor’s men.

Only a handful of French guns were positioned at the centre of Victor’s line and they spat back their defiance, trading shots with the batteries immediately opposite. All the time Victor’s guns were whittled down by the enemy until, no more than a quarter of an hour after the cannonade had begun, the last French eight-pounder was struck squarely on its carriage and a hail of splinters cut down half of the gun crew. The survivors turned and ran for the lines of infantry waiting behind them.

The Austrian guns fell silent, then a moment later the sound of drums and trumpets reached Napoleon. Through the dense bank of gunpowder smoke emerged columns of enemy infantry, the sun glinting off their musket barrels and the officers’ gorgets and swords as they waved their men forward. There was a lull in the noise of battle as the enemy came on, and the French waited, grimly. Then, when it seemed that the two lines could not get much closer, Napoleon heard the order to present arms echo down the French line.Thousands of musket barrels swept up and out, aiming at the enemy no more than seventy paces away.

‘Fire!’Victor bellowed, his booming voice carrying across the battlefield. Stabs of light and swirls of smoke billowed out along the French line like a ribbon of soiled cotton. From his slightly elevated position Napoleon could see the leading ranks of the enemy column tumble down as the volley of musket balls tore into them. But they held their ground, re-formed and marched a short distance closer before deploying into a firing line. Victor’s men managed to get off two more volleys before the Austrians returned fire. Then the fight was swallowed up in an ever-thickening bank of acrid yellow smoke that hung across the battlefield.

Napoleon waited until he was certain that the French line was holding along its front, and then rode forward to General Victor. The veteran greeted him with a salute and a wry shake of the head. ‘They caught us out nicely, sir.’

Napoleon ignored the comment as he returned the salute. ‘You must hold here for as long as possible. Lannes and Murat are moving up to support you. I’ve sent for Desaix.’

‘Desaix? He won’t be able to reach us until long after this battle is over.’

‘Perhaps,’ Napoleon conceded. ‘But he might. Meanwhile we have to hold the Austrians back as long as we can, until tonight at least.Then we’ll concentrate our forces and go on to the attack tomorrow.’