Eighteen arhats refer to the eighteen arhats who are immortal and protect the Buddha in Buddhist legends, and come from sixteen arhats plus two venerable ones. They are all historical figures and disciples of Sakyamuni.
Sixteen arhats were mainly popular in the Tang Dynasty, and eighteen arhats began to appear at the end of the Tang Dynasty. In the Song Dynasty, eighteen arhats prevailed. The appearance of eighteen arhats may be related to the traditional preference of eighteen in China culture.