Zizhi Tongjian, vol. 195: "上以其強盛,恐後難制,癸亥,拜其二子皆為小可汗,各賜鼓纛,外示優崇,實分其勢。" (Fearing their growing strength and potential difficulty in controlling them later, in the year of Guihai, both of Yinan’s sons were appointed as Lesser Khagans, each bestowed with a drum and banner. This outwardly showed high honor but was actually meant to divide their power.)