Explanation:
Pulakeshin II was a Chalukya king who ruled over Deccan region of India during the 7th century. Harsha, on the other hand, was a powerful ruler of North India who ruled from Kannauj. Harsha wanted to expand his empire and march into the Deccan region to establish his dominance. However, Pulakeshin II did not allow him to cross the Narmada river.

Reasons for Pulakeshin II Stopping Harsha:
There could be several reasons why Pulakeshin II stopped Harsha from crossing the Narmada river. Some of the possible reasons are:

- Geographical Barrier: The Narmada river is one of the longest rivers in India, and it flows from east to west, dividing the Indian subcontinent into two halves. The Deccan region lies south of the Narmada river, and it was considered a difficult terrain to conquer due to its rugged terrain and dense forests. Pulakeshin II might have used the Narmada river as a natural barrier to protect his kingdom from external invasions.

- Military Strategy: Pulakeshin II was a powerful ruler who had a well-trained army. He might have realized that Harsha's army was no match for his army, and he could easily defeat Harsha in a battle. However, he also knew that Harsha was a cunning strategist, and he might use guerrilla warfare tactics to weaken Pulakeshin's army. By stopping Harsha at the Narmada river, Pulakeshin II could avoid a direct confrontation with Harsha and force him to retreat.

- Political Rivalry: Harsha was a powerful ruler who had ambitions to unify India under his rule. His conquests had already made him a popular ruler among the people of North India. Pulakeshin II might have feared that Harsha's expansionist policies could threaten his own kingdom. By stopping Harsha at the Narmada river, Pulakeshin II could send a message that he was not afraid of Harsha and could protect his kingdom from external threats.

In conclusion, Pulakeshin II stopped Harsha from crossing the Narmada river to protect his kingdom from external invasions, use military strategy and avoid political rivalry.

Pulakeshin 2 had defeated Harshavardhan on the bank of river Narmada in 618 AD.