Mahabharata 1.90.63

1.90.63

pāṇḍostu dve bhārye babhūvatuḥ kuntī mādrī cetyubhe strīratne || 63 ||

"And Santanu married Ganga, who bore him a son Devavrata who was afterwards called Bhishma. And Bhishma, moved by the desire of doing good to his father, got him married to Satyavati who was also called Gandhakali. And in her maidenhood she had a son by Parasara, named Dwaipayana. And upon her Santanu begat two other sons named Chitrangada and Vichitravirya. And before they attained to majority, Chitrangada had been slain by the Gandharvas. But Vichitravirya became king, and married the two daughters of the king of Kasi, named Amvika and Amvalika. But Vichitravirya died childless. Then Satyavati began to think as to how the dynasty of Dushmanta might be perpetuated. Then she recollected the Rishi Dwaipayana. The latter coming before her, asked, 'What are thy commands?' 'She said, 'Thy brother Vichitravirya hath gone to heaven childless. Beget virtuous children for him.' Dwaipayana, consenting to this, begat three children, viz., Dhritarashtra, Pandu, and Vidura. King Dhritarashtra had a hundred sons by his wife, Gandhari in consequence of the boon granted by Dwaipayana. And amongst those hundred sons of Dhritarashtra, four became celebrated. They are Duryodhana, Duhsasana, Vikarna, and Chitrasena. And Pandu had two jewels of wives, viz., Kunti, also called Pritha, and Madri. One day Pandu, while out a-hunting, saw a deer covering its mate. That was really a Rishi in the form of a deer.