sentence1: The fortress was besieged again from 22 December 1813 until 14 April 1814 by French troops under the command of General Zoller before the Bavarian garrison surrendered .
sentence2: From 22 December 1813 to 14 April 1814 , the fortress was once again besieged by Bavarian troops under the command of General Zoller , before the French garrison capitulated .