《资治通鉴·唐纪·唐纪四》
唐高祖派人与窦建德联系，窦建德送唐高祖同母妹妹同安公主随使者一同返回长安。
上遣使与窦建德连和，建德遣同安长公主随使者俱还。
Emperor Gaozu sent people to contact Dou Jiande, and Dou Jiande sent Tang Gaozu's mother's sister, Princess Tong'an, back to Chang'an with the messenger.