Then there was the question of the timing of the main attack on the Pratzen Heights. Too soon and the enemy would spot the danger and be able to respond in time to block the thrust.Too late and the French right might be broken and both armies would merely have wheeled round, locked on each other like a pair of battling stags. Napoleon knew that the attack would have to be perfectly timed to achieve its purpose, and the decision when to give the order would depend on how long the weakened centre and right of the French line along the Goldbach could hold its ground. He stared to the right and cursed the heavy mist. It might well be useful to conceal the French positions from the enemy, but it also concealed the men from the eyes of their commander and it was essential that Napoleon knew exactly what was happening along the length of his battle line throughout the coming day.

He turned to Berthier.‘I want regular reports from the commanders, down to brigade level. On the half-hour, understand? Make sure that there are adequate messengers to carry it out.’

‘Yes, sire.’ Berthier added a note in his log and then turned to one of his junior staff officers to pass on the Emperor’s order. As they talked behind him, Napoleon closed his eyes for a moment, and mentally projected a map of the surrounding area in his head. Marshal Lannes was on the left flank, with orders to hold any Austrian attacks. Murat’s cavalry would form up in support of Lannes, and be launched in pursuit of the enemy if things went well. If they didn’t it would be Murat’s responsibility to cover the retreat of whatever was left of the Grand Army.Then there was Bernadotte’s corps, entrusted with the defence of the Zurlan, but ready to exploit any weakness in the enemy line should the opportunity arise. Behind the Zurlan was the Imperial Guard acting as a reserve, and the two divisions of Soult’s corps chosen to lead what should be the decisive attack - if the battle went as planned, Napoleon reminded himself. He allowed himself a wry smile as he recalled something he had heard years before: once a battle began the very first casualty of the day was always the plan. Just one division, commanded by General Legrand, was entrusted with holding back the main weight of the enemy attack along the bank of the Goldbach. Legrand must hold on until Davout’s hard-marching corps arrived on the right flank and could support him.

‘Dawn, sire.’ Berthier drew his Emperor’s attention to the east, where the dull pink orb of the sun was rising over the crest of the Pratzen Heights, picking out the Russian and Austrian troops massing to attack.