The period that followed the death of Devapala marked the Downfall of Pala Empire and also its disintegration. Till the time of Devapala, Bengal was reckoned as an important power in the history of ancient India. After the death of Devapala, the throne was ascended by Vigrahapala I, who ruled for a short period, with not much achievement to his credit. He was succeeded by his son Narayanapala about 854 A.D. He was a man of religious and soothing disposition so during his long career he did not have any military victory to his credit. According to some historians Narayanapala was one of the weakest kings of Pala lineage.
In 860 A.D. the Rashtrakutas had invaded his Empire and defeated him. The Pratiharas struck several blows to the Pala Empire and consequently disintegrated their glorious empire. Bhoja I snatched the imperial hold of North India from Narayanapala. Bhoja I by this means extended his own control upto Bihar, on the ruins of the Pala Empire. Mahendrapala, son of Bhoja Pratihara followed a policy of aggression against the Palas seized Magadha and even the territory of north Bengal from Narayanapala. The Paharpur Pillar Inscription states that Mahendrapala Pratihara had conquered a part of the Rajshahi district and the other inscription states that his sway had extended upto the region of Dinajpur. In these circumstances the king of Kamarupa and the Sailodbhaba dynasty of Orissa withheld their allegiance for the Palas and became independent kingdoms. Towards end of Narayanapala`s rule he was able to recover North Bengal and South Bihar from the powerful contenders Pratiharas, and left it as a legacy to his successor Rajyapala.
Rajyapala however reigned for a very short period of time. He was succeeded by his son Gopala II and the latter was succeeded by Vigrahapala. The long period of eighty years, when these three kings were in throne, was marked by increase in disintegration and decline of the Pala Empire. Moreover a series of foreign invasions led by the Chandellas, Kambojas and Kalachuriyas had shattered the Pala Empire. The Kalachuriyas made devastating inroads in Bengal, right up to eastern Bengal. During the reign of Vigrahapala II, a hilly tribe called Kambojas had captured western and Northern Bengal. Eastern and southern Bengal disregarded the supremacy of Palas and became independent under the Chandra Dynasty.
Towards the end of 10th century the paternal territory of Rajyapala and his two successors consisting of Bengal and Magadha, were divided into three well-defined independent kingdoms. These included Chandra kingdom of eastern and Southern Bengal, Kamboja kingdom of Northern and Western Bengal, the Pala kingdom (proper), under Rajyapala and his two successors, comprising Anga and Magadha. The period of stagnation continued for more than a hundred years, covering the reigns of generations of kings. During this period the Pala kings hardly attempted for expansion, they were lacking in energy and not dominant enough to check foreign invasions.
Pala dynasty did see a glorious revival under Mahipala I. Though Mahipala could not regain all the lost territories, a major portion of it was recaptured. But after him it was again towards a decline which was temporarily revived by Ramapala. With the death of Ramapala the strength of the dynasty vanished. Ramapala was succeeded by Kumarapala, Gopala III and Madanapala for a period of thirty five years. The circumstances leading to disaster of Pala dynasty are unclear. Kamarupa was lost gradually. Bhojavarman of Eastern Bengal overthrew the allegiance to Pala supremacy and became independent. King Anantavarman Chodaganga of Kalinga had annexed Orissa. The rigorous blow to Palas came from twp karnatic dynasties, Senas of Radha and House of Nanyadeva. Madanapala lost Gauda and North Bihar to his opponents. He had control over Central Bihar only. That was also lost by his successor though it is unknown as to who it was. Hence the Palas lost their foot hold completely.
