Srimad Bhagavata Purana

In the Tretā age people are devoted to ritual performances and severe austerities. They are not excessively violent or very lusty after sensual pleasure. Their interest lies primarily in religiosity, economic development and regulated sense gratification, and they achieve prosperity by following the prescriptions of the three Vedas. Although in this age society evolves into four separate classes, O King, most people are brāhmaṇas.