Background
Mahabharta describes the events that happened till the present kaliyuga,in the beginning of the yuga approximately 5000 years ago Lord Shri Krishna was his devotee and friend Arjun tells geeta . Their dialogue is one of the greatest philosophical and religious dialogues in human history this conversation took place before a fierce battle the great Yadavi war took place between the hundred sons of Dhritarashtra and their paternal cousins Pandavas.
Dhritarashtra and Pandu would have been brothers and they would have been born in the Kuru dynasty they were the descendants of King Bharat and it was because of King Bharat that the Mahabharata name was born. Elder brother Dhritarashtra did not get the kingdom because he was blind by birth, therefore his brother Pandu got it.
Due to death of King Pandu at his young age, Yudhishthir,Bhima,Arjun,Nakul and Sahadev his five sons were brought up by Dhritarashtra who became king for some time, in this way, Dhritarashtra and pandu or the sons of both grew into a single dynasty.Both of them were experts in Dronacharyas Kshatriya knowledge and were guided by grandfather Bhismdev.
However, Dhritarashtras sons and especially his son Duryodhana, who was extremely cruel to Pandavas had a strong haterd for Pandavas and it was Dhritarashtras wish that his own sons and not Pandavas sons should get the kingdom. Similarly with the consent of Dhritarashtra, Duryodhana conspired to kill the yong son of pandu. Pandavas were able to save their lives due to the careful protection of Vidur and maternal cousins brother Shri Krishna.
Shri Krishna means not just any common man but God himself. He would have taken an earthly incarnation and having been born in the royal family of that time he would have appeared like a royal son.In this way as a relative and the protector of Santan Dharma or as a maternal relation therefore he supporting and protecting the Pandus sons. Finally the cunning Duryodhana challenge the Pandavas to playing grambling. During the final contest, Duryodhana and his beloved Pandavas wife Draupadi tried to humilate him by disrobing him in the royal court.Her shame was spared by the divine intervention of Lord Shri Krishna, but the due to cheating in that game of chance the Pandavas lost their kingdom and had to suffer thirteen years of exile.
After returning from exile,the Pandavas requested by Duryodhana to return their rightful kingdom, but he flatly refused.Being Kshatriyas, it was their duty to rule and so they asked for only five villages, but Duryodhana replied insolently that he would not give even a piece of land equal to the tip of a needle.
Up to now, the Pandavas had been consistently tolerant. However now it was necessary to fight. Some of the king's from all over the world took the side of Pandavas and some of the Kauravas. However Shri Krishna himself went to Duryodhana assembly as a peace massenger and requested him to avoid the war, when his request was rejected, the war was certain. The Pandavas, who were very virtuous knew Shri Krishna as the Lord himself but the sons of Dhritarashtra could not understand them however due to the insistence of the war hungry opposing party, Shri Krishna himself was available as a guide if the politician Duryodhana had asked for Shri Krishna's army, the Pandavas were equally eager to have Shri Krishna in a person
Thus Shri Krishna became Arjuna's charioteer and began to drive the chariot of the great archer. Now we have reached the movment when Bhagvadgeeta begins.The two parties are standing in a battle Dhritarashtra eagerly asks his secretary Sanjaya what the two parties have done.