<human>:  Why did Napoleon lose at the Battle of Vienna?
<bot>: Napoleon’s army was too small. He had a total of 25,000 men, but the Austrians had 50,000. Napoleon’s army was also poorly trained and equipped, and they were not familiar with the terrain in the area. Napoleon’s army was also badly organized and did not coordinate their movements well. The Austrians were able to use their superior numbers and their knowledge of the terrain to defeat Napoleon.