Su Wu

Su Wu lived during the same period as did Li Ling, and was sent by the Emperor Wu upon a mission of peace to the Hsiung Nu. By the time he reached the Court of the Khan, however, relations between the Chinese and the Barbarians were again strained, and he was taken prisoner. Various attempts were made to induce him to renounce his allegiance to China; he was thrown into prison and subsisted for days on the moisture which he sucked from his clothes, but all efforts to undermine his loyalty failed, and eventually he was sent to tend sheep on the grazing fields of the steppes. Years passed, Wu Ti, the "Military Emperor," died, and his successor  Chao Ti made peace with the Central Asian tribes and sent envoys to ask for the return of the faithful Su Wu. The Khan replied that he was dead, but the envoy was able to answer that such could not be the case, as, not long before, the Emperor himself while hunting in his park had shot a wild goose, and had found a letter from Su Wu tied to its leg. The loyal official was therefore sent back to China. He had gone off in the prime of life; when he returned, in 86 b.c., he was a broken-down, white-haired old man.