Vishnupurana 4.3.31

4.3.31

athaitāmatītānāgatavartamānakālatrayavedī bhagavānaurvacaḥsvāśramānnirgatyābravīt //

When the boy had grown up, and was capable of reflection, he said to his mother one day, "Why are we dwelling in this hermitage? where is my father? and who is he?" His mother, in reply, related to him all that had happened. Upon hearing which he was highly incensed, and vowed to recover his patrimonial kingdom; and exterminate the Haihayas and Tálajanghas, by whom it had been overrun. Accordingly when he became a man he put nearly the whole of the Haihayas to death, and would have also destroyed the Śakas, the Yavanas, Kámbojas, Páradas, and Pahnavas, but that they applied to Vaśisht́ha, the family priest of Sagara, for protection. Vaśisht́ha regarding them as annihilated (or deprived of power), though living, thus spake to Sagara: "Enough, enough, my son, pursue no farther these objects of your wrath, whom you may look upon as no more. In order to fulfil your vow I have separated them from affinity to the regenerate tribes, and from the duties of their castes." Sagara, in compliance with the injunctions of his spiritual guide, contented himself therefore with imposing upon the vanquished nations peculiar distinguishing marks. He made the Yavanas shave their heads entirely; the Śakas he compelled to shave (the upper) half of their heads; the Páradas wore their hair long; and the Pahnavas let their beards grow, in obedience to his commands. Them also, and other Kshatriya races, he deprived of the established usages of oblations to fire and the study of the Vedas; and thus separated from religious rites, and abandoned by the Brahmans, these different tribes became Mlechchhas. Sagara, after the recovery of his kingdom, reigned over the seven-zoned earth with undisputed dominion.