Raja Prithu (also known as Jalpeswara) ruled the Kamarupa kingdom in north-eastern India from 1195 to 1228 AD, in what is now the state of Assam. In 1206, he defeated Muhammad bin Bakhtiyar Khalji's expansionist designs, and in 1226 AD, he defeated Ghiyas-ud-din Balban, the ninth sultan of the Slave Dynasty of Delhi.
In 1206, Muhammad bin Bakhtiyar Khalji launched an invasion of Tibet in order to pillage the Buddhist monasteries' treasures and seize control of Bengal's old trade route to South East Asia, which required him to march through the kingdoms of Kamarupa and Sikkim. To lure Bakhtiyar Khalji away from his centre of operations, Prithu allowed Bakhtiyar Khalji's army to advance unchecked into his territory. He used a scorched-earth strategy, denying his opponent the opportunity to resupply. When the invading army realised it's folly and attempted to retreat, he demolished a bridge across a deep bridge that Bakhtiyar Khalji's army had already passed, effectively cutting off their retreat. The embattled invading troops were then subjected to heavy and aggressive attacks from all sides.
Bakhtiyar Khalji's entire force of 12,000 horsemen was virtually decimated, with only about 100 surviving. His mission to conquer Tibet was a complete failure, and he was assassinated shortly after his return.
Ghiyas ud din Balban also attacked Kamarupa in 1226 and advanced as far as present-day Guwahati before being defeated.
In 1228, Raja Prithu was killed in battle with Nasir-ud-din Mahmud. He was succeeded by Sandhya as the ruler of Kamarupa.
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- Kamtapur Movement in North Bengal Geoethno-Environmental and Historical Perspective, Soumendra Nath Nag, PhD Thesis, University of North Bengal
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