Pratip the king of Hastinapur, had three sons: Devapi, Shaantanu and Balhik. Devapi chose to become an ascetic. Few Rucha's of the Rg Veda are assigned to Devapi. Balhik declined to become the king. Thus Shaantanu became the king of Hastinapur. Balhik, his son (Somdatta) and grandson (Bhurishrava) stayed in Hastinapur, till their death in the great war. Balhik, Somdatta and Bhurishrava took part in the daily court activities.
Shantanu's wife Ganga gave birth to 7 sons, all died in infancy. The 8th son Devavrat survived infancy. Ganga died when Devavrat was about 8 years old.
Did Ganga really kill her first 7 babies? Was it an act of madness or did they die of natural causes?
Matsyagandha (one who smelled like a fish) worked as a boatman, on the river Yamuna. She begot a son from Sage Parashar. Sage Parashar treated her for her body odour. She gained a sweet smell, and later was called: Yojangandha (one whose sweet smell spread one yojana around) or Satyavati. This child was born on an island of river Yamuna. Thus he was called Dwaypayan (one born on a dweep). Dwaypayan grew up to be a very learned sage. He was responsible for compiling the Ved. For this huge task he gained the name Vyas (the compiler).
Shaantanu wanted to marry Satyavati. Satyavati's father agreed on the condition that Satyavati's son would be the king of Hastinapur. Dejected Shantanu returned to Hastinapur. Devavrat about 8 years old, went with some ministers to Satyavati's father. He vowed that he would never claim the throne of Hastinapur. Satyavati's father was not satisfied, he said what if your sons claim the throne? So Devavrat swore that he would not create progeny and remain unmarried. Satyavati's father was satisfied. Shaantanu praised Devavrat for his oath and married Satyavati. Devavrat gained the name Bheeshm (one who took a terrible oath).
Did Bheeshm take this oath in hurry? Did he ever repent for it? Later did it so happen that only for those words his image became larger than him, and all he could do was just follow it?
Two sons were born to Satyavati: Vichitravirya and Chitrangad. Soon Shantanu died. Young Chitrangad was killed in a battle with a Gandharva called Chitrangad. Adolecent Vichitravirya was coronated as the king.
Bheeshm kidnapped the daughters of Kashiraj: Ambaa, Ambika and Ambalika during their Swayamvar. On reaching Hastinapur, the wedding of the three sisters was announced to Vichitravirya, the king of Hastinapur.
So far Ambaa was okay with prospect of marrying Bheeshm. But when they realised that they were to be married to Vichitravirya, Ambaa refused. Why? Was something wrong with Vichitravirya? Was he too young? Was he physically / mentally unfit?
She declared her love for king Shaalwa, in the presence of ministers. Bheeshm made arrangements to send Ambaa to Shaalwa. (or did he have to make arrangements?) Shaalwa refused to marry Ambaa, as she had stayed with Bheeshm. Dejected Amba asked Bheeshm to marry her. He declined because of his vow to remain unmarried. Furious, Amba swore to avenge Bheeshm. She asked his Guru, Parashuram to persuade him to marry her, but Parashuram failed. She tried to gain military support to battle Bheeshm. All her attempts were futile. Angered, insultated and hurt, Ambaa comitted sucide.
Ambika and Ambalika married Vichitravirya. Vichitravirya died soon after this marriage. Bheeshma continued his position as a caretaker of the state. The kingdom of Hastinapur was without king. So Satyavati invited her son, Sage Vyas to impregnate Ambikaa and Ambaalikaa. Ambikaa bore a blind son Dhrutarashtra. Satyavati requested Vyas that Ambikaa should be given another chance. But rather than face the ugly Vyas again, Ambikaa sent her maid, who bore a son Vidur. Meanwhile Ambaalikaa bore a son Paandu, from Vyas.
Though elder, Dhrutarashtra was blind, thus Pandu became the king of Hastinapur.
Yadav dynasty was established by King Yadu, son of King Yayati. The Yadav King Shurasena's daughter Prutha, was adopted by his cousin, King Kuntibhoj. She came to be known as Kunti.
Kunti was appointed to serve their guest Sage Durvas. During this time she gave birth to a baby boy: Karna. Was he fathered by Sage Durvas?  She discarded the newly born baby in a river. He was found and adopted by a charioteer Adhirath and his wife Radha.
Bheeshm arranged the marriage of Dhruturashtra to Gandhari, the princess of Gandhar. Bheeshm also arranged the marriage of Vidur. King Pandu married Kunti, the first marriage in years that was not arranged by Bheeshm. Bheeshm later arranged Pandu's second marriage to the beautiful Madri, the princess of Madra. (Did he chose someone very very beautiful, only to belittle Kunti? Whom Pandu had chosen?)
Months later, Pandu successfully completed the digvijay expedition. A feat not achieved by his father, and uncles, including Bheeshm. One day a vaidya (doctor) diagnosed him as infertile. Mahabharat says, Pandu accidentally killed a sage in the woods, who then cursed Pandu that he would not be able to produce progeny. I think the sequence of events must have been the other way round … the vaidya diagnosed Pandu infertile, and Pandu killed him so that the knowledge of his disease remained a secret.
Pandu did not inform anybody of his condition. He just walked out with his wives to the Himalaya. He decided he would have sons by some men of his choice. And then one day return with his sons to Hastinapur. Pandu declared he was leaving for Himalaya. Dhrutarashtra did not stop him. Was it because he wanted the kingship? Bheeshm did not stop him. Was it because Pandu was too independent for Bheeshm to manipulate?
Once in the Himalaya, Pandu took his wives in confidence. Kunti and Madri agreed to cooperate. In the following 5 years Kunti bore 3 sons, and Madri bore 2. Their biological fathers remain unknown. Maybe they were fathered by the sages who lived in the Himalaya. Maybe they were fathered by Vidur . So far everything had gone according to Pandu's plan. Now was the time to return and reclaim the throne.
Meanwhile in Hastinapur, one day after the birth of Bheem, Duryodhan was born to Gandhari. In the following years a 100 sons and many daughters were born to Dhruturashtra's many wives.
On a fateful day, Pandu and Madri died in a tragic accident. Kunti returned to Hastinapur with 5 children and the dead bodies of Pandu and Madri. Pandu and Madri were given a royal funeral in Hastinapur. [Adi Parv, Sambhava Parv:CXXVII]
After Kunti's arrival, Satyavati, Ambika and Ambalika retired to the forest.
Poverty ridden Dronaacharya was unable to support his wife Krupi and son Ashwathama. He decided to get help from Drupad. His childhood friend, and now the king of Panchal. King Drupad insulted Dron by saying "Friendship is only among equals." Drona decided to avenge Drupad with the help of his disciples. In search of good pupils, he came to Hastinapur to Krupachrya (minister in Dhruturashtra's courts, and Krupi's brother).
Bheeshma called upon Dronacharya to teach Kaurav and Pandav. Many princes from other states, Ashwathama and Karna studied in Drona's school. Out of the love for his son, Drona gave the knowledge of Narayan-astra only to Ashwathama. Drona also loved Arjun, and to see that no one is better that Arjun, he asked Ekalavya for his thumb. During this time Kaurav tried to kill Bheema twice. Duryodhan also killed the charioteer of Yudhishthir. Kunti and the Paandav lived in this precarious situation.
Kaurav & Pandav completed their education. On the last day, in a competition, 22 year old Karna challenged 17 year old Arjun to a duet. Bheem nullified this challenge by inferring that Karna was a Sutaputra. Duryodhan befriended Arjun's compititor, by making Karna the King of Angadesh.
After the education of the princes was complete, Drona asked his pupils to defeat Drupad as his Gurudakshina. Kaurav and Karna failed to defeat Drupad. Arjun and Bheema defeated Drupad and brought him as a prisoner to Drona. Drona returned the kingdom of Southern Paanchal to Drupad and released him. Drona who was now the king of Northern Panchal, extended a hand of friendship to Drupad as his equal.
Enraged Drupad brought up his son Drusthadyumna with the ambition "avenge Drona". The twin sister of Drusthadyumna was the beautiful Druapadi. Who was also called Yadynasena, Panchali and Krushnaa.