《资治通鉴·唐纪·唐纪一》
三月，己酉，唐王以齐公李元吉为镇北将军、太原道行军元帅，都督十五郡诸军事，允许他有权随机行事。
三月，己酉，以齐公元吉为镇北将军、太原道行军元帅、都督十五郡诸军事，听以便宜从事。
In March, on the day of the rooster, the Prince of Tang appointed Duke Qi, Li Yuanji, as Marshal of the Northern Army and Commander-in-Chief of the Taiyuan Expeditionary Force, and gave him the authority of Grand Comtur of Military Affairs of 15 counties, permitting him to act as he sees fit.