Bhagiratha, the great grandson of Sagara brings down the divine river Ganges to earth to expiate the sins of the sons of Sagara. Rtuparna is the next prominent king in the dynasty made famous by his association with Nala, the king of Nisadas. Nala married Damayanti, the daughter of Bhima, the Yadava king of Vidarbha. The delightful story of their marriage and the unhappy sequel of his subsequent temporary loss of his kingdom and destitution through gambling, is in the Mahabharata told to Yudhisthira suffering in similar circumstances.
After a long eclipse (corresponding to the ascendency of the solar dynasty under Mandhata), the Paurava line is revived by Dusyanta, a near contemporary of Bhagiratha. He marries Sakuntala, the daughter of Visvamitra and begets Bharata.Bharata is crowned as a cakravartin and later gives his name to the dynasty, to the great fratricidal war between the Kauravas and Pandavas, and to India itself (i.e. Bharatavarsa). His fifth successor Hastin shifts the capital to a place in the upper doab and calls it Hastinapura, after himself.
Soon after Hastin, the Bharata dynasty is divided into four separate lines – the most well-known being the main Paurava line and the Pancala line. The Pancala king Divodasa is celebrated in the Rigveda as the destroyer of 99 forts of the dasyu Sambara.His sister was Ahalya, the wife of Gautama. She was deceived by Indra and expelled into the forest by her husband on account of her infidelity.
The solar line once again ascends under the benevolent kingship of Raghu, Aja and Dasaratha. The story of Rama, Dasaratha's son, forms the subject of the poem Ramayana by Valmiki. The intrigues of his step-mother Kaikeyi result in the exile of Rama, his wife Sita and his brother Laksmana to the forest. In the forest, Sita is abducted by Ravana, the king of raksasas and imprisoned in Lanka, his capital. Rama forms an alliance with the monkeys and the bears of the forest and lays a siege of Lanka. Ravana is ultimately defeated and slain by Rama. He then returns back to Ayodhya with his wife Sita and ascends the throne.
With Rama’s death, the Treta yuga comes to a close and the Dvapara commences. After Rama the solar dynasty goes into permanent decline.
source : wikipedia