There was a triangular struggle for the control of the Ganga-Yamuna Doab and the adjoining lands between the Pratiharas of Jalor, the Palas of Bengal, and the Rashtrakutas of the Deccan from the 8th to the 10th century. The absence of prominent rulers like Harsha had created a power vacuum in North Indian politics. Taking advantage of this situation, emerging powers engaged in a struggle for dominance in Northern India. This struggle is known as the “Tripartite struggle for supremacy.” It had several interesting features. All three rivals considered the conquest of the imperial city Kanauj as the ultimate goal of their ambitions. A scholar has aptly remarked that just as Babylon was to the martial races of Western Asia and Rome was to the Teutonic barbarians, Mahodaya Sri (Kanauj) was to the rising dynasties of the 8th and 9th centuries AD.
Rivalry between Dharmapala and Vatsaraja: The reign of Dharmapala was marked by the struggle between the Palas, Pratiharas, and Rashtrakutas for mastery over Northern India. Dharmapala’s northern antagonist was Vatsaraja Pratihara of Rajputana and Malwa. From the closing decades of the 8th century, both rivals nurtured imperial dreams. While Dharmapala was expanding the boundaries of his kingdom towards the west, Vatsaraja was extending his kingdom towards the east. The possession of the city of Kanauj was the competing objective for both. Dharmapala conquered Magadha and expanded his influence. It was probably his conflict with Vatsaraja in Allahabad that made their conflict inevitable. The first round of the struggle opened with a battle between Dharmapala and Vatsaraja, in which the former was defeated. Pratihara records state that Dharmapala fared poorly in this opening battle. The victorious Pratihara army reached as far as the Bay of Bengal, and Vatsaraja finally captured Kanauj.
Dhruva-Vatsaraja Conflict: Before Vatsaraja could enjoy the fruits of victory, the Rashtrakuta king Dhruva appeared on the scene. When Vatsaraja was returning from Bengal with a great amount of plunder, he was defeated by Dhruva. Dhruva not only took away his immense booty but also his two white umbrellas, symbolizing his control over Bengal and Gauda. Dhruva inflicted a crushing defeat on Vatsaraja, forcing him to live as a refugee. Dharmapala was Dhruva’s next target, as he marched against the Pala king in the east and defeated him in battle. Vatsaraja appointed Indrayudha as his vassal and returned to the Deccan.
Dhruva-Dharmapala Conflict: After defeating Vatsaraja, Dhruva also defeated Pala king Dharmapala. However, Dharmapala quickly recovered from the setback of defeat and continued his struggle with the Pratiharas for control over North India. The Khalimpore Copper Plate of Dharmapala, the Munger Copper Plate of Devpala, and the Bhagalpore Copper Plate of Narayanapala shed light on Dharmapala’s conquests in North India. Dharmapala conquered Kanauj and deposed its ruler, Indrayudha or Indraraja, placing his own nominee on the throne of Kanauj. He kept him as his vassal and assumed sovereignty over Mahodaya or Kanauj.
Dharmapala-Nagabhatta II Conflict: Dharmapala did not have the fortune of enjoying his vast suzerainty without facing further challenges from his archenemy, the Pratiharas. Nagabhatta II, the son of Vatsaraja Pratihara, consolidated his authority by forming an alliance with the kingdoms of Sindhu, Vidarbha, Kalinga, and Andhra against his rival. The Pratihara records describe his exploits against Dharmapala, as he initiated the second round of the Tripartite struggle by attacking Kanauj and defeating Chakrayodha, the protege of Dharmapala.
Nagabhatta II and Govinda III: Before Nagabhatta could completely crush the power of his eastern adversary, his triumphant career was interrupted by the invasion of the Rashtrakuta king, Govinda III. The motives behind Govinda III’s northern adventure are unknown. However, Nagabhatta was disastrously defeated by Govinda III, and both Dharmapala and Chakrayudha willingly submitted to the authority of the Rashtrakuta conqueror for the time being. However, the Rashtrakutas were not permanent conquerors. Govinda III soon retreated to the Deccan without consolidating his authority in the North. The withdrawal of the Rashtrakutas cleared the way for Dharmapala to revive his power in the North. Dharmapala’s empire did not suffer any further setbacks during the rest of his life, and he spent his remaining years in peace.
Nagabhatta II fought many battles against the Rashtrakutas. Initially, he retreated to save himself from disaster. In the second battle, he was defeated by Karakka Raja. After the death of Govinda III (814 AD), Nagabhatta II saw an opportunity with Amogha Varsha, who was a 13-14-year-old boy and unlikely to withstand against him. Nagabhatta II was able to defeat his rival and assumed the title of “Parambhattaraka Maharaja Dhiraja Parameshwara Nagabhattadeva.
Devapala-Ramabhadra: Ramabhadra, the successor of Nagabhatta II, was a weak ruler who faced troubles from his enemies. Devapala of Bengal took advantage of the situation and disturbed the peace in the eastern parts of Ramabhadra’s empire. It is possible that Ramabhadra also lost Bundelkhand to Devapala.
Devapala & Bhoja: The Pratihara Kingdom suffered a decline due to the invasion of Devapala. Ramabhadra’s son and successor, Bhoja or Mahira Bhoja, attempted to restore the fortunes of his dynasty. Despite initial success against Devapala, Bhoja was eventually defeated by him.
Bhoja-Amogavarsha: Bhoja’s ambition to expand southward brought him into conflict with Amogavarsha I, the Rashtrakuta king. Bhoja was old, but Amogavarsha I was even older and a devoted follower of Jainism. When King Bhoja interfered in the war of succession in the Gujarat line of the Rashtrakutas, Dhruva II of Gujarat managed to repel his forces. However, in a subsequent battle, Amogavarsha I defeated Bhoja. This victory over King Bhoja is mentioned in various inscriptions. King Bhoja, unwilling to accept his defeat, retaliated and as a result, the Gujarat line of the Rashtrakutas was completely eradicated by King Bhoja. It appears that Bhoja was defeated near Ujjain because he was caught unprepared.
After Devapala, the Tripartite struggle among the Palas, Pratiharas, and Rashtrakutas continued for a prolonged period. However, over time, the strength of the struggle weakened.