The correct answer is Dharmapala. Important PointsDharmapala founded the famous Buddhist monastery at Vikramashila. It became eminent as Nalanda. Dharmapala became ruler after Gopala in about A. D. 780. He undertook the expansion of his empire. Dharmapala defeated Indrayudha, the king of Kanauj, and installed his nominee Chakrayudha to the throne of Kanauj. Rashtrakuta king, Dhruva defeated Dharmapala near Monghyr (Bihar) in a battle. He was the real founder of the Pala Dynasty because he extensively expanded the boundaries of his empire, and made the Palas a dominant power in northern and eastern India. He was the 2nd ruler of the Pala dynasty. He built the great Vihara at Somapuri in Verendri and the Vihara in Paharpur. Additional InformationAfter Dharmapala, his son Devapala became the ruler. He was the mightiest Pala king. He conquered ‚¬€œ Pragjotishpur (Assam) and Utkala (Odisha). He patronized the Vikramashila University and Nalanda University. Famous poet Vajradatta who was the author of Lokesvarashataka was one of the gems of his court. After the death of Devapala ended the period of ascendancy and a period of stagnation followed which gradually led to decline and disintegration until Mahipala rejuvenated the rule of the dynasty. Ballal sen was the second ruler of the sen dynasty (1160‚¬€œ1179). He was the son and successor of Vijaya Sena. He was succeeded by Lakshmana Sena.