《汉书·传·外戚传上》
冬天快要过去的时候，公主替充国交纳二十匹马以赎罪，这才免去他的死罪。
冬月且尽，盖主为充国入马二十匹赎罪，乃得减死论。
As winter was about to end, the princess paid twenty horses on Chong Guo's behalf to redeem his crime, and this spared him from being executed.