Berthier hesitated, then nodded. He gathered up his notebooks, placed them in his large leather despatch case and quietly left the room. Napoleon rose stiffly from his chair, then carried it across to the remains of the small fire glowing in the grate. He carefully placed some more logs on the flames and sat back, closing his eyes, surrendering to the comforting warmth. He pushed troubling thoughts aside and pictured himself on the lawn at Fontainebleau, in the summer, playing with his infant son.

‘Sire.’ A hand shook his shoulder gently.

Napoleon woke immediately, eyes wide as he looked into Berthier’s excited features.

‘What is it?’

‘Marshal Oudinot is here with me, sire.’ Berthier stepped aside to reveal Oudinot.

‘So?’

‘It’s best if the marshal explains himself.’

‘Explains what?’ Napoleon eased himself up. He glanced at the clock on the mantelpiece. It was three o’clock in the morning. He had been asleep for over five hours, he realised, angry with himself.

Oudinot stepped forward. ‘I’ve come straight from my headquarters. sire. I’ll come to the point.’

‘Please do.’

‘A column of reinforcements under General Corbineau joined my command this evening.’

‘I know about that. He commands a brigade that was sent for from Vilna.’

‘That’s right. Corbineau intended to cross the Berezina at Borisov on his way to join us, but the day before yesterday he discovered the town was in Russian hands. So he questioned a local peasant to see if there was another place to cross the river. The peasant guided him to a ford eight miles north of Borisov, at the village of Studienka.’

‘I know it, but there’s no ford there.’

‘None marked on the map, sire. But Corbineau crossed there.’ Oudinot could not help smiling. ‘He says the water was no more than waist deep.’

There were several flashes in the night as the firing on the far side of the river faded away. Corbineau and his men had succeeded in storming the two guns that had been left to cover the unmarked ford. They had earlier waded across the freezing river, muskets held high, and driven off a company of Russian infantry before turning on the guns. Evidently the enemy had also known about the ford, but since it had not been marked on any maps they had posted only a token force to protect the crossing place. In the distance, to the south, there was an occasional rumble of artillery as Oudinot’s men carried out their diversionary attacks opposite Borisov. As Napoleon had hoped, the Russian forces strung out along the far bank had hurried south, marching to the sound of the guns.