《元史·列传·卷八十六》
宪宗九年，元世祖忽必烈南征至彰德，召瑛问计。瑛说： 汉唐以来，人君能赖以立国的，就是法、兵、食三件事而已。
岁己未，世祖南伐至相，召见问计，瑛从容对曰： 汉、唐以还，人君所恃以为国者，法与兵、食三事而已。
The ninth year of Emperor Xianzong, the Mongol ruler Kublai Khan's southern expedition reached Zhangde, he summoned Ying and asked him for advice. Ying said: Since Han and Tang, the three things that the ruler of a country can rely on to establish himself are: law, military and food.