still unknown. After Gopala II, Dharmapala's line came to an end for reasons which are not known yet. Dharmapala's descendants, if any, were passed over as Dharmapala's younger brother, Vakapala's lineage assumed the throne. First period of decline Shortly afterwards, the empire gradually started disintegrating. Vakapala's grandson and Jayapala's son, Vigrahapala I abdicated the throne after a brief rule, and became an ascetic. Vigrahapala's son and successor Narayanapala proved to be a weak ruler. During his 54-year long reign, Mihira Bhoja defeated the Palas. Encouraged by the Pala decline, the King Harjara of Assam assumed imperial titles. Naryanapala's son Rajyapala ruled for at least 32 years, and constructed several public utilities and lofty temples. Earlier it was thought that his son Gopala III lost Bengal after a few years of rule, and then ruled only Bihar. However, it has been debunked by his Bhagalpur inscription, in which he granted a Brahmin two villages in Pundrabardhanabhukti in Northern Bengal, signaling his control over it. His son and the next king, Vigrahapala II, had to bear the invasions from the Chandelas and the Kalachuris. During his reign, the Pala empire disintegrated into smaller kingdoms like Gauda, Radha, Anga and Vanga. Kantideva of Harikela (eastern and southern Bengal) also assumed the title Maharajadhiraja, and established a separate kingdom, later ruled by the Chandra dynasty. The Gauda state (West and North Bengal) was ruled by the Kamboja Pala dynasty. The rulers of this dynasty also bore names ending in the suffix -pala (e.g. Rajyapala, Narayanapala and Nayapala). However, their origin is uncertain, and the most plausible view is that they originated from a Pala official who usurped a major part of the Pala kingdom along with its capital. Revival under Mahipala I Mahipala I recovered northern and eastern Bengal within three years of ascending the throne in 978 CE.H also recovered his capital, Gauda, which had been lost to he Kambojas. He also recovered the northern part of the present-day Burdwan division. During his reign, Rajendra Chola I of the Chola Empire frequently invaded Bengal from 1021 to 1023 CE to get Ganges water and in the process, succeeded to humble the rulers, acquiring considerable booty. The rulers of Bengal who were defeated by Rajendra Chola were Dharmapal, Ranasur and Govindachandra, who might have been feudatories under Mahipala I of the Pala Dynasty. Rajendra Chola I also defeated Mahipala, and obtained from the Pala