The origin of mooncakes at Mid-Autumn Festival?

The origin of the mooncake at the Mid-Autumn Festival:

One fall in the early Tang Dynasty, a group of merchants from Tupan (ancient Tibet) came to Chang'an and brought many gifts (refined cakes) as tribute to the Tang Emperor Li Yuan. On the night of the Mid-Autumn Festival, Tang Gaozu invited his ministers to enjoy the moon and share the cakes offered by the Tupan merchants. The emperor and his ministers ate the cakes while enjoying the moon and renamed the cakes as mooncakes, which were the earliest mooncakes.

Mooncakes (pinyin: yuè bǐng) are one of the most famous traditional Chinese pastries, which are eaten during the Mid-Autumn Festival. The mooncake is round and round, and is shared by the family, symbolizing unity and harmony.

Extended information:

The mooncake, which symbolizes reunion, is also supposed to have begun in the Ming Dynasty. If the Ming Dynasty about the moon cake and the Mid-Autumn Festival folklore, should be able to see the historical trajectory of the moon cake meaning reunion: the Mid-Autumn Festival after the moon festival, the whole family are sitting around together to share the moon cake and moon fruit (moon festival offerings). Because the moon is full and the mooncake is round, and it is eaten by the whole family, the symbol of the mooncake representing the reunion of the family has gradually been formed.

Mooncakes are filled with seeds of plant-based raw materials, such as walnuts, almonds, sesame seeds, melon seeds, hawthorn, lotus seed paste, red beans, jujube paste and so on, which have certain health effects on the human body.

Reference:

Mooncakes-Baidu Encyclopedia