 Complete the following phrase:  Chinese legends of geese include the story of Su Wu: in the days of old, old Su Wu, spent 19 years, captive of Xiongnu. There is a story about Su Wu which became a common allusion in Chinese poetry. Su Wu was an historical figure, however his legend has evolved into the folk realm. There are thus many variations of his story, though much can be attested to historically. The rival Chinese and Xiongnu empires battled in the 