The Battle of Plassey in 1757 marked a turning point in Indian history, as it led to the establishment of British political rule in India. The victory of the British East India Company over the Nawab of Bengal laid the foundation for British colonial control over the Indian subcontinent.

The event that led to the establishment of British political rule in India was the Battle of Plassey.

Background:
- The British East India Company arrived in India in the early 17th century with the primary intention of establishing trade relations.
- Over time, the Company expanded its influence and started to intervene in local politics and conflicts.
- The Company gradually gained control over several coastal areas and established trading posts.

Causes of the Battle of Plassey:
- The Battle of Plassey took place on June 23, 1757, in the town of Plassey (now Palashi) in Bengal.
- Siraj ud-Daulah, the Nawab of Bengal, opposed the growing influence and encroachments of the British East India Company.
- The Nawab was particularly angered by the Company's fortification of Calcutta (now Kolkata) without obtaining permission.

Course of the Battle:
- Siraj ud-Daulah gathered a large army and besieged Calcutta, capturing the city in June 1756. The incident came to be known as the Black Hole of Calcutta.
- The British East India Company responded by sending a naval force under the command of Robert Clive to retake Calcutta.
- Clive formed an alliance with Mir Jafar, a discontented noble of the Nawab's court, who aspired to become the Nawab himself.
- On the day of the battle, Mir Jafar and his forces defected to the British side, turning the tide in their favor.
- Despite having a larger army, Siraj ud-Daulah was defeated due to betrayal and lack of support from his own men.
- The battle lasted only a few hours, and the British emerged victorious.

Consequences of the Battle:
- The Battle of Plassey marked a turning point in British colonial rule in India.
- The defeat of Siraj ud-Daulah weakened the Mughal Empire's control over Bengal and opened the door for the British East India Company to establish political dominance.
- Mir Jafar was installed as the new Nawab of Bengal, becoming a puppet ruler under British control.
- The victory at Plassey gave the British East India Company a foothold in Bengal and set the stage for further expansion and consolidation of their rule in India.
- It paved the way for the establishment of British political rule over large parts of the Indian subcontinent in the following decades.