From Chen Zi'ang's (
陈子昂, Early Tang) 《
登幽州台歌》:
前不见古人,后不见来者。念天地之悠悠,独怆然而涕下 (No ancients before me, no successors behind; thinking of heaven and earth's vastness, alone and grieving, tears fall.) Written on the Youzhou (near modern Beijing) terrace where Yan general
乐毅 had been honored - Chen laments that no wise ruler of his own era recognizes him.