《旧唐书·本纪·卷十四》
二十七日，吐突承璀的军队从京城出发，宪宗亲临通化门慰问送行。
己亥，吐突承璀军发京师，上御通化门劳遣之。
On the 27th, Tutuo Chengcui’s army set out from the imperial capital, and Emperor Xianzong visited the Tong’hua Gate in person to see them off.