《资治通鉴·唐纪·唐纪二十八》
戊子，唐玄宗命令尚书左丞萧嵩与京兆、蒲、同、岐、华州长官负责选拔府兵以及未入兵籍的状丁共一十二万人，称为 长从宿卫 ，每年分为两班，轮流值勤，并且明令地方州县不得再向这些人征发任何其他徭役。
戊子，命尚书左丞萧嵩与京兆、蒲、同、岐、华州长官选府兵及白丁一十二万，谓之 长从宿卫 ，一年两番，州县毋得杂役使。
On wu-zi, Emperor Xuanzong of Tang ordered the Minister of the Left Xiao Song and the magistrates of Jingzhao, Pu, Tong, Qi, and Hua states to select 120,000 soldiers from the palace guards and the men who had not yet been enlisted in the army, to be called Changcong Suwei. Divide them into two shifts each year and have them take turns on duty, and also order the local prefectures and counties to stop sending these people to perform any other corvee labor.