Where does the etiquette of eating cake on birthday come from?

People are familiar with eating cakes and blowing out candles on birthdays. This custom originated in Greece.

In ancient Greece, people believed in themis, the goddess of the moon. At her annual birthday celebration, people always put honey cakes and many lighted candles on the altar to form a sacred atmosphere to show their special respect for the goddess of the moon. Later, with the passage of time, because of their love for children, the ancient Greeks always liked to put cakes and other things on the table when celebrating their birthdays. On them, they put many small lighted candles and added a new activity-blowing out these lighted candles. They believe that lighted candles have mysterious power. If the birthday child makes a wish in his heart at this moment, and then blows out all the candles in one breath, then the child's good wish will surely come true. So blowing out candles has become a small program with auspicious significance at birthday parties, and gradually developed into an interesting activity of blowing out candles at birthday parties or banquets for children, adults and even the elderly.