長阿含經 5.p63

5.p63

“Vāsiṣṭha, the world today has the names of these four castes. The name of the fifth community is ‘ascetic.’ Why is that? Vāsiṣṭha, at some point there was a person in the warrior assembly who was disillusioned with his own teaching. He shaved his hair and beard and put on Dharma robes. This was when the name ‘ascetic’ first appeared. At some point, people from in the priest caste, householder caste, and worker caste had was disillusioned with their own teaching. They shaved their hair and beard and put on the Dharma robe. They were called ‘ascetics.’