When Tolstoy remarked that every unhappy family is unhappy in its own way, he might have been referring to the Kauravas and Pandavas, the principal families of the Mahabharata. After all, his correspondence with Gandhi reveals that the history of the Bhagavad-Gita was known to the great Russian author.
And no family has ever been unhappier than that of Bhishma and his political grandchildren, the Kauravas. For while Bhishma Gangeya, son of Shantanu is the nominal grandfather of the royal line, he is the family patriarch only indirectly.
In many ways, the Princess Amba is central to the conflict which reaches its dénouement at the battle of Kurukshetra. Had it not been for Bhishma's vow of celibacy--his promise to his father never to rule and never to have children-- he might have married the Princess, sired a generation of heirs and ruled the city of elephants peacefully.