When the last of the officers had left the shuttered drawing room a sentry closed the door. Berthier remained seated at the table, having returned to his routine of updating the dwindling figures from the strength returns in his notebooks. Napoleon twisted one of the silver buttons on his greatcoat.

‘What do you think, Berthier?’

Berthier replied without looking up. ‘Think of what, sire?’

‘My abandoning the army.’

Berthier lowered his pen and looked up. ‘I think it may shortly become a necessity, sire.’

‘And will it be a mistake? Speak honestly, my friend.’

‘If you are captured by the Tsar, then you can expect little mercy from him given what happened to Moscow, and the other towns and villages we have marched through. Even if your life is spared, you can be sure that you will be humiliated, and France along with you. So, yes, sire. If it comes to it, then you must do everything in your power to avoid being taken by the Russians.’

‘Everything?’ Napoleon asked quietly.

‘Yes, sire,’ Berthier nodded. He had understood. ‘Even that.’

‘My surgeon has some phials of poison. I have always ensured that he carried them in case of such an emergency. I will keep one on my person from now on. As a precaution.’

‘It would be wise, sire.’

Both men were silent for a while before Napoleon stirred. ‘Of course, if I abandon the army, they will say I am a coward, my enemies.’

‘You must expect that. But the people of France will understand that it was necessary. They will know that as long as you are alive France must be counted a great nation. While you live, you inspire our soldiers to acts of greatness, and you awe our enemies. Soldiers can be replaced. You, sire, can not.’

Napoleon searched Berthier’s face for any sign of flattery or insincerity, but his chief of staff seemed utterly convinced by his own words. Napoleon smiled warmly at him. ‘You, too, cannot be replaced, my friend. You are the word to my thought. It is through your words that my will is exercised and France has won its greatness on the battlefield. I should have thanked you before now.’ Napoleon felt an uncomfortable surge of guilt as he recalled the numerous occasions he had slighted or insulted Berthier. He shifted uncomfortably and gestured towards the door. ‘I must think, alone. Leave your books for tonight. Go and find something to eat, some wine to drink and a bed by a warm fire.’