Yuga-Vibhāga and Kāla-Pramāṇa
Measures of Time and the Four Yugas
सर्वसाधारणा ह्येते त्रेतायां वै भवं त्युत / वर्णाश्रमव्यवस्थानं तेषां ब्रह्मा तदाकरोत्
sarvasādhāraṇā hyete tretāyāṃ vai bhavaṃ tyuta / varṇāśramavyavasthānaṃ teṣāṃ brahmā tadākarot
O Bhava, in the Tretāyuga all these were common to all; then Brahmā established for them the order of varṇa and āśrama.