Yuga-Vibhāga and Kāla-Pramāṇa
Measures of Time and the Four Yugas
तदा प्रमुदिता वर्णास्त्रेतायां धर्मपालिताः / क्रियावन्तः प्रजावन्तः समृद्धाः सुखिनस्तथा
tadā pramuditā varṇāstretāyāṃ dharmapālitāḥ / kriyāvantaḥ prajāvantaḥ samṛddhāḥ sukhinastathā
Then, in the Tretā age, the varṇas upheld by dharma were filled with joy—active in sacred rites, blessed with offspring, prosperous, and happy.