Satyavati was afraid that Hastinapur would be left without any king after the death of her second son, Chitrangad, in a battle. She then decided to get her younger son Vichitravirya married and get an heir. It was at the same time she heard about the kingdom of Kashi holding up a Swayamvar for the three princesses – Amba, Ambika and Ambalika.
Queen Satyavati ordered Bhishma to get the princesses married to Vichitravirya. Bhishma blatantly refused the queen to obey as it was a Swayamvar and their kingdom had not gotten an invitation as the relationships were severed when the princess of Kashi was to marry Bhishma. Bhishma also knew that Vichitravirya would be easily defeated by the other princes. Satyawati ordered Bhishma to go and fight against the princes. A helpless Bhishma went to Kashi and fought King Shalya who was defeated by him. He returned to the kingdom with the three princesses.
Ambika and Ambalika were very happy to marry Vichitravirya and raised no objection to the marriage. They were happy to get so many riches and palaces. However, Amba refused boldly and said that she wanted to marry Prince Shalya and she secretly loved him. She had not told her father about the same as he would win the princesses in the Swayamvar. Bhishma realized his mistake and took Amba back to Shalya who refused to marry her as he was defeated by Bhishma. He came back and Amba saw no option but to marry Bhishma. Bhishma refused to marry her because of his oath.
Amba tried for 6 years in the kingdom to convince him before she finally asked Parashurama to defeat Bhishma in a duel and convince him. The battle ended in a stalemate and a shattered Amba went to pray to Shiva, who showed him the path to become Shikhandi and seek her revenge.
Ambalika and Ambika were both happy in their marriage with Vichitravirya. However, there was no heir to the throne and day by day, Vichitravirya’s health deteriorated on account of his alcohol consumption and unhealthy habits. It was also said that Vichitravirya was impotent and thus the name. He finally succumbed to Tuberculosis and they were left with an heir to the throne.
Satyavati then ordered Ved Vyasa to perform the ritual of Niyoga with the two queens. Niyoga is to be performed by a brother in law to the queens of his brother. The queens thought it would be Bhishma but were scared to see Vyasa – a hermit who had returned after ages of meditation in their room.
As a result, Ambalika gave birth to Pandu who was born pale as she was pale and lifeless during the act while Ambika gave birth to Dhritarashtra, who was blind as Ambika had closed her eyes during the act.
Satyavati saw the outcome and realized that none of her grandsons would make a suitable king so she requested Vyas to perform Niyog again with Ambalika. Ambalika stepped back at the last moment and replaced herself with Parishrami, her maid. The act gave birth to Vidur, the ablest yet cursed brother of all.