To Viscount Castlereagh, K.G.

Vienna, 12th March, 1815

I have but little to add to my dispatch regarding Buonaparte’s invasion of France. The intention is, as soon as it shall be ascertained that he can make head against the King, to assemble 3 large corps; one in Italy, solely Austrian, which will consist of 150,000 men; one on the Upper Rhine, Austrian, Bavarian troops of Baden and Wurtemberg, which will eventually consist of 200,000 men, but will at first consist of only the troops of Bavaria, Baden, and Wurtemberg; the third on the Lower Rhine, consisting of the Prussian corps of Kleist, the Austrian garrison of Mayence, and other troops on the Moselle, to be joined to the British and Hanoverians in Flanders. Of this corps they wish me to take the command. The Russian army, 200,000 men, is to be formed in reserve at Wurtzburg, &c. &c.; the remainder of the Prussian army, in reserve, on the Lower Rhine.

The Emperor of Russia seems reconciled to the notion of the old system, of managing the great concern in a council, consisting of himself, the King of Prussia, and Schwarzenberg. He expresses a wish that I should be with him, but not a very strong one; and, as I should have neither character nor occupation in such a situation, I should prefer to carry a musket.

The Emperor intimated to me this day that, in case the movement of his troops became necessary, he could do nothing without the assistance of money from englands. I told him I should write to your Lordship upon the subject by this courier; and that, in my opinion, the first measure to be adopted was, one something of the nature of the treaty of Chaumint, in which he agreed; and afterwards to think of subsidiary, if England could grant such a thing.

It is my opinion that Buonaparte has acted false or no information, and that the King will destroy him without difficulty, and in a short time. If he does not, the affair will be serious one, and a great and immediate effort must be made, which will doubtless be successful. All the measures above stated to be in contemplation tend to this effort; and it will remain for the British Government to determine how far they will act themselves, and how far second the effort of the Continent.

I now recommend to you to put all your force in the Netherlands at the disposition of the King of France. I will go and join it if you like it, or do any thing else that Government choose. I think we shall have settled our concerns here, and signed the treaty, if the Spaniard does not impede us, by the end of the month. We shall have finished every thing that is important much sooner, so that I shall be ready whenever you please to call for me.