求翻译：相传明洪武初年，大将徐达攻下元朝残余势力盘踞的元大都北京，捷报传到首都南京，正在下棋的明太祖朱元璋欣喜若狂，即传谕中秋节普天同庆，并将当初反元大起义时传递信息的月饼赏赐臣民。月饼从此成为中秋节“法定”的食品，非食不可了。是什么意思？

Legend, in the early Ming Hongwu, General xuda captures most of the residual forces entrenched in the Yuan dynasty Yuan Beijing, marked its spread to the capital, Nanjing, being chess mingtaizu Zhu Yuanzhang's ecstatic, that Oracle Mid-Autumn Festival celebrated and anti-Yuan had great uprising mooncakes reward people of passing information. Mid-Autumn Festival Moon has since become "official" food, non food is not available.