What led to the decline of Gurjara Pratiharas?

The Gurjara Pratiharas declined due to dynastic strife. The final blow came in the form of a raid by Indra III of the Rashtrakutas that devastated the Gurjara Pratihara capital of Kannauj.

For further reading check the following articles:

• Harshavardhana
• Palla Empire
• Early Medieval Northern India