《新唐书·列传·卷十一》
罗艺很高兴，不加提防，随即调拨兵士三千人，车数百辆、马驴千余匹前往借粮，开道全都留下而不予遣返。于是北与突厥连兵，且与罗艺断绝往来，重称燕王，并与刘黑闼共同进犯内地。
艺悦，不为虞，更发兵三千、车数百、马驴千往请粟，开道悉留不遣，遂北连突厥，告绝于艺，复称燕，与刘黑闼联兵入寇。
Luo Yi was very happy and was not defensive, so he immediately dispatched 3,000 soldiers, hundreds of chariots and over 1,000 horses and donkeys to borrow food, but Kaidao kept all the emissaries and did not send them back. He then joined forces with the Turks to the north, severed ties with Luo Yi, and once again claimed the title of King of Yan, and joined forces with Liu Heita to invade the interior.