Dhritarashtra, Pandu & Vidur
So that the family line did not die out, Satyavati summoned her son Vyasa to impregnate the two queens. Vyasa had been born to Satyavati of a great sage named Parashar before her marriage to Shantanu. According to the laws of the day, a child born to an unwed mother was taken to be a step-child of the mother's husband; by that token, Vyasa could be considered Shantanu's son and could be used to perpetuate the Kuru clan that ruled Hastinapur. Thus, by the Niyog custom, the two queens each had a son of Vyasa: to the elder queen was born a blind son called Dhritarashtra, and to the younger was born an otherwise healthy but extremely pale son called Pandu. To a maid of these queens was born a son of Vyasa called Vidur. Bheeshm brought up these three boys with great care. Dhritarashtra grew up to be the strongest of all princes in the country, Pandu was extremely skilled in warfare and archery, and Vidur knew all the branches of learning, politics, and statesmanship.
With the boys grown, it was now time to fill up the empty throne of Hastinapur. Dhritarashtra, the eldest, was bypassed because the laws barred a disabled person from being king. Pandu, instead, was crowned. Bheeshm negotiated Dhritarashtra's marriage with Gandhari, and Pandu's with Kunti and Madri. Pandu expanded the kingdom by conquering the sorrounding areas, and brought in considerable war booty. With things running smoothly in the country, and with its coffers full, Pandu asked his elder brother to look after the state affairs, and retired to the forests with his two wives for some time off.