The Tripartite Struggle (785–816) were a series of wars in northern India fought over the control of the throne of Kannauj, which during that time was equivalent to having imperial status over all of Aryavarta.

Even before the struggle over Kannauj started, Dantidurga, the founder of the Rashtrakuta Empire, had defeated Nagabhata I of the Pratihara dynasty, as evident from the Dashavatara Temple inscription of Dantidurga at Ellora and the Sanjan inscription of Amoghavarsha I, both belonging to the Rashtrakuta dynasty which states that Dantidurga (r. 735–756) performed a religious ceremony at Ujjayani, and the king of Gurjara-desha (Gurjara country) acted as his door-keeper (pratihara),[7][8] suggesting that the Rashtrakuta king had subdued the Pratihara king who was ruling Avanti at that time.

The king of the Gurjaras, Vatsaraja, the grand-nephew of Nagabhata I,[10] expanded the small principality founded by his ancestor into a powerful kingdom in northwestern India.

The incumbents of the Kannauj throne at that time, the Ayudha dynasty were weak rulers and the accession of Indrayudha triggered the first great war.

However, the ambitious king of the South, Dhruva (of the Rashtrakuta royal family) decided to intervene in the ongoing conflict of the northern kingdoms.

[11] Following the departure of Dhruva, Dharmapala grabbed the opportunity and invading the kingdom of Kannauj around 791,[a] defeated Indrayudha and installed his brother Chakrayudha as his vassal, clearly avoiding annexation.

He then held an imperial court at Kannauj to crown Chakrayudha, which was attended by the rulers of Bhoja,[b] Matsya,[c] Madra,[d] Kuru,[e] Yadu,[f] Yavana, Avanti, Gandhara and Kira.

After securing the Vindhya passes under his loyal brother Indra, he invaded the Gurjara kingdom though Bhopal and Jhansi and defeated Nagabhata near Gwalior.

Dharmapala prepared for the inevitable and Nagabhata, along with his vassals — Kakka of the Jodhpur Pratihara family, Vahukadhavala, the Chalukya chief of southern Kathiawar and the Guhilot Sankaragana, began the final invasion of Bengal.

In the Battle of Monghyr, Nagabhata's forces soundly defeated those of Dharmapala, finally resulting in a Pratiharan victory,[22] and marking the end of the decades-long tripartite struggle.