Mooncakes usually refer to cakes that people eat on the Mid-Autumn Festival, which are usually round.
According to historical records, the first time cake was associated with the Moon in the Mid-Autumn Festival, it was on August 15th that General Li Jing conquered the Huns and returned home. Tang Gaozu took the Hu cake presented by Turpan merchants, smiled and pointed out that the moon said, "Hu cake should be invited to toad". At the time of the Northern Song Dynasty, this kind of cake was called "palace cake", which was popular in the court, but also spread to the people. At that time, it was commonly known as "small cake" and "moon group". Later, it evolved into a circle, meaning reunion and beauty. According to "Knowledge in Luozhong", Tang Xizong ordered the imperial kitchen to give cakes to the new Jinshi with HongLing on the Mid-Autumn Festival. But it was not called moon cake at that time.
The word moon cake was first seen in Wu Zimu's Dream of Liang Lu in the Southern Song Dynasty. At that time, the moon cake was rhombic, coexisting with chrysanthemum cake and plum cake, and it was "available at all times, so you can call it whenever you want." It can be seen that the moon cakes at this time are not only eaten in the Mid-Autumn Festival. As for the origin of the term moon cake, there is no way to verify it. However, Su Dongpo, a famous scholar in the Northern Song Dynasty, left a poem that "a small cake is like chewing the moon, with crispness and satiety in it", which may be the origin of the name of moon cake and the basis of its practice. There are a lot of records about moon cakes since the Ming Dynasty. At this time, moon cakes are round and only eaten in the Mid-Autumn Festival, which is the main offering for the popular Mid-Autumn Festival in the Ming Dynasty. "A Brief Introduction to the Scenery of the Imperial Capital" says: "On the 15th of August, when the moon is sacrificed, the fruit cake will be round." "Home moonlight is located in the moon, worship to the moon, then burn moonlight paper, withdraw the supply, scattered family will be over. Moon cakes and fruits are rewarded, and the cakes are two feet in diameter. "
The widely circulated story that Zhu Yuanzhang used moon cakes to convey the news of the uprising on August 15th is inconsistent with the historical facts, because Zhu Yuanzhang did not lead the uprising, but only joined Guo Zixing's team and took Guo's adopted daughter as his wife, the latter being Ma Huanghou. If the legend of using moon cakes to convey the news of the uprising is true, it is very likely that Zhang Shicheng did it. But this legend proves on the other hand that the Yuan Dynasty had the custom of eating moon cakes in the Mid-Autumn Festival.
Moon cakes symbolize reunion, and they should have started in the Ming Dynasty. If we look at the data about moon cakes and Mid-Autumn Festival in the Ming Dynasty, we should be able to see the historical track of the reunion of moon cakes: after the Mid-Autumn Festival, the whole family will sit around and share the moon cakes and fruits (offerings for the moon). Because the moon cake is also round and shared by the family, it gradually forms the implication that moon cakes represent family reunion.