Why Winter Solstice come from?

In the northern areas of China:

There is an old saying in Beijing that goes, “have wontons (hun tun) on the Winter Solstice and noodles on Summer Solstice.” It is said that during the Han Dynasty, the northern tribes often harassed the northern border of China, and the people there suffered from the invasion. At that time, the two leaders of the tribes with the surnames “Hun” and “Tun” were the cruelest. People hated them so much that they made dumplings filled with spiced minced pork, and named them “huntun” (wonton). By eating them, people released their hatred of the brutal leaders, and prayed for peace. Because they happened to make the dumplings on the day of the Winter Solstice, people decided to have wontons on that day.

In the south areas of China:

People in the south have the custom to eat Red Bean Glutinous Rice with their families on the night of the Winter Solstice. It is said that there was a man with the surname Gonggong, who did all kinds of evil when he was alive. When he finally died on the Winter Solstice, he turned into a ghost bringing all kind of diseases to people. The ghost, however, was afraid of red beans. Thus, on the Winter Solstice, people cook rice with red beans to drive out evil spirits and prevent diseases.