On 22 June, in face of the worsening situation in Saxony and northern Bavaria, Napoleon's brother Jérôme, who was also King of Westphalia, left Kassel with a force of 15,000 men including his Royal Guard Division. On the same day the Austrian forces had occupied Leipzig but were quickly forced to retreat by the arrival of Jérôme's troops. By 26 June, Jérôme had retaken the city and two days later the Westphalians clashed with the Austrians and Brunswickers for the first time.