What is the origin of traditional years?

In ancient times, there lived a monster named Nian in the river. Nian came out on the last day of the year to harm people. Therefore, people want to take refuge in the mountains on this day. One year, when people were going up the mountain, an old man with a white beard came and stayed alone, asking about the situation. On that day last year, grandpa wore a big red coat, posted Spring Festival couplets on the door and set off firecrackers. Nian was so scared that he immediately returned to the river and never dared to hurt anyone again. Over time, this became a custom in 2008.