All the while Napoleon carefully scrutinised the regular intelligence reports sent to him by Davout. As soon as the threat to Vienna became clear Archduke Charles had turned his army round and set off along the north bank of the Danube in a bid to reach his capital city before the French. There was little chance of that, Napoleon calculated, since the Austrian army had always marched at a ponderous pace. The only news that concerned him came from Italy, where Archduke Charles’s brother, Archduke John, had bested the French army there. It was possible that John might march back towards Vienna in an attempt to combine the Austrian armies against Napoleon.

Early in May, the spires and roofs of the Austrian capital came within sight of the French army and Napoleon gave the order for the artillery to prepare to bombard Vienna. Before the guns could open fire the gates of the city opened and a small party of civilians rode out.

‘I wonder what they want?’ Berthier mused as he raised his telescope and watched them cautiously approach the French pickets. He turned to his Emperor. ‘Maybe they want to sue for peace already.’

‘I would hope so,’ Napoleon replied. ‘But if they intend to defend Vienna, then this time I will not hesitate to flatten the city. There will be no third chance for Emperor Francis to defy me.’ Napoleon gestured for the telescope and squinted through the eyepiece. There were five men in civilian clothes, together with a small mounted escort from the city’s militia.

‘Have them brought to the main battery,’ Napoleon instructed Berthier.‘I’ll meet them there. Might as well let them see what they can expect if they fail to meet my demands.’

‘Yes, sire.’ Berthier nodded and wheeled his horse away to carry out the order. Napoleon turned his gaze from the approaching horsemen to the defences of the city beyond. There were a handful of forts guarding the approaches to Vienna, and then the walls. However, there were no signs of life in any of the forts, and no flags or regimental standards flying over them. He lowered the telescope with a slight frown and muttered, ‘What the hell are they playing at?’