Mahabharata 1.1.71

1.1.71

ṛṣibhiśca tadānītā dhārtarāṣṭrānprati svayam |
śiśavaścābhirūpāśca jaṭilā brahmacāriṇaḥ || 71 ||

Pandu, after having subdued many countries by his wisdom and prowess, took up his abode with the Munis in a certain forest as a sportsman, where he brought upon himself a very severe misfortune for having killed a stag coupling with its mate, which served as a warning for the conduct of the princes of his house as long as they lived. Their mothers, in order that the ordinances of the law might be fulfilled, admitted as substitutes to their embraces the gods Dharma, Vayu, Sakra, and the divinities the twin Aswins. And when their offspring grew up, under the care of their two mothers, in the society of ascetics, in the midst of sacred groves and holy recluse-abodes of religious men, they were conducted by Rishis into the presence of Dhritarashtra and his sons, following as students in the habit of Brahmacharis, having their hair tied in knots on their heads. 'These our pupils', said they, 'are as your sons, your brothers, and your friends; they are Pandavas.' Saying this, the Munis disappeared.