The alliance between Britain and Austria agreed in Vienna on 20 June, in the aftermath of the Austrian defeat at Marengo, included two terms which were crucial to the next events: the grant of a subsidy to Austria, and a reciprocal agreement by Austria not to make a separate peace with France. The armistice which Bonaparte had agreed with General Melas, the Austrian commander in Italy, on the day after Marengo was therefore to be only temporary. He followed it up with a peace offer, and then with an armistice in Germany, which was followed in turn by a peace conference, but Austria, assured of British support and British gold, was able to use the period of the armistice to recover militarily, and had not been beaten so decisively as to be forced to a peace.

In the interval of the Austrian truce Bonaparte renewed his peace approach to Britain. In London was Louis Guillaume Otto, a Germanborn French diplomat, the French commissioner in matters of prisoners of war, who organised paroles and exchanges of prisoners. The British had posted a major to do the same job in Paris, but Otto was not an army man. He was from Alsace, no doubt originally Ludwig Wilhelm, and had an American wife, and so he presumably spoke at least three languages. He was a welcome guest at London dinner tables, and an accomplished diplomat, but he was in fact kept on a tight rein by his masters in Paris. He had been sent to London originally to open negotiations at the end of the previous year, 1799; those had failed, in part due to Bonaparte’s clumsiness in addressing the king rather than his ministers, but Otto was still in London and available. On 24 August he wrote again to Lord Grenville, the Foreign Secretary, first with a routine request for passports for some couriers, and second to report that the British ambassador in Vienna, Lord Minto, had given a note to the Austrians who had asked that it be sent to London through France. (This was in fact official notification of the Anglo-Austrian treaty of alliance.)