After Draupadi married the Pandavas, word reached their cousins, the Kauravas, that they were alive and well. Most people were happy, but wicked Duryodhana and his associate Karna conspired against their cousins. Karna proposed going to war with the Pandavas, but wiser heads prevailed. Bhisma, Vidura, and Drona all convinced king Dhrtarastra to welcome the Pandavas back to their kingdom of Hastinapura with open arms. This was what dharma required. And so the five Pandava brothers, along with their wife Draupadi and their mother Kunti, returned to their kingdom with a resplendent entrance. The people of the city were so excited and happy to see the returning princes.
After the Pandavas had stayed awhile in Hastinapura, king Dhrtarastra proposed a solution to ease the tensions between the two sets of cousins (the Pandavas and the Kauravas)—the kingdom would be split evenly in two, with the Kauravas ruling from Hastinapura, and the Pandavas ruling from a place called Khandavasprastha. The Pandavas agreed and moved to their new home, which was just a forest when they arrived. But out of that forest, the five princes built a beautiful, luxurious, and prosperous city called Indraprastha. It was one of the most beautiful cities in the world.
And so the kingdom was divided. The Kauravas ruled half from Hastinapura, and the Pandavas ruled the other half from Indraprastha.