What was the issue over which the three powers of northern India contested with one another?

a. The Issue of Contest:

From the time of Harshavardhana the centre of political activities in northern India shifted from Pataliputra to Kanauj. The importance of Kanauj did not diminish even after the death of Harsha.

This will be evident from the fact that for the next two hundred years the Indian rulers of both the northern and southern India were struggling among themselves for domination over Kanauj.

The three powers engaged in the conflict were the Palas of Bengal, the Pratiharas of western India and the Rashtrakutas of the Deccan.

b. Significance:

At the initial stage of the conflict the Pala king of Bengal, Dharmapala occupied Kanauj by defeating Vatsyaraj, the Pratihara king.

At one time, again, the Rashtrakuta King Dhruva with a view to establishing his hold over Kanauj defeated both Vatsyaraj and Dharmapala.

Dharmapala soon recovered from the set back and once again appeared in full strength at Kanauj. However, without going into details it may be said that the tripartite conflict for control over Kanauj continued for a few generations.

c. Results:

More important than the conflict itself was the impact it had on the three powers. Though all the powers had to spend money for military purposes no one could control Kanauj permanently.

Moreover, the struggle weakened all the three powers as the respective rulers could not look after the administration of their own kingdoms.