苏武
Su Wu (140 – 60 BC) was held captive for 19 years, returning to China in 81 BC: 4 poems collected in the "Wen Xuan" are only questionably attributed to him. However, at the time, it was not uncustomary to confuse the persona of a poem with the person of the author. There is a story about Su Wu which became a common allusion in Chinese poetry. According to this story, during the beginning of his captivity in the Xiongnu empire Su Wu was treated harshly, to the point it is said of having to eat the lining of his coat for food and to drink snow which he melted for water. Later Su was elevated in status, even it is said given a wife who bore him children. Upon the Han emperor sending an ambassadorial mission toward the territory in which he was being held, the Xiongnu ruler (the chanyu) wished to conceal the presence of Su Wu, presumably in order avoid diplomatic complications; but, Su Wu hearing of this tricked the chanyu by claiming that he had sent a message to the emperor by tying it to the leg of a goose, and accordingly, that since his presence was already known to the Chinese delegation that any attempts at concealing his presence would be viewed as unseemly. This is at least part of the origin of the use of the image of a flying goose as a messenger, carrying tied to its foot (perhaps symbolically) a letter between two people separated so far seasonally north and south that a migrating goose could be conceived as a possible mode of communication.