After Harsha, who ascended to throne in 606 and was the great king. He was man of great energy and great gifts. After his death, the whole of north India was ruled by rivaling local dynasties. There was a confusion all around. Not a single ruler was there who could unite the warring factions. After his death, usurper Arunashva seized Kanyakubja. He attacked Wang Hsuan tse who came with a small detachment of troops as a help from Chinese emperor to Harsha. Wang escaped and gathered an army from Assam, Tibet & Nepal and captured Arunashva and took him to China as a captive.
After this Bhaskaravarman of Assam extended his rule westwards and occupied Magadha in the process. Meanwhile 2nd Gupta dynasty with Adityasena as the king revived in latter half of 7th century, Yashovarman established his empire at Kanyakubja. In the following two centuries, two great dynasties, the Palas of Bihar & Bengal and Gurjara-Pratihara of Kanyakubja divided the hegemony of North India.
Dharmapala marks the apogee of Pala dynasty. After hid death, his successor Devpala was still an important king and had contacts with king Sailendra of Sumatra and Palas became patrons of Buddhism. They also introduced Buddhism to Tibet.
After Palas, Gurjara-Pratihara were most powerful kings of North India. They successfully resisted the Arabs who had already occupied Sind. Their two notable kings Mihir Bhoj and Mahendrapala pushed back the Palas and were the overlords up to Bengal in the East. Rastrakutas continually harassed them and temporarily succeeded in occupation of Kanyakubja in 916. These raids weakened the Pratiharas and turned their attention away from gathering trouble in the west. After this in 10th century they lost their power and many feudatories formed