《三国志·蜀书·先主传》
《易经》乾卦九五中说 飞龙在天 ，大王应当像龙一样飞升，登上帝位。
易乾九五 飞龙在天 ，大王当龙升，登帝位也。
In the Yijing, the Qian hexagram, Line 9, it says, “Flying dragon in the heavens.”, so the great king should ascend like a dragon and mount the imperial throne.