Bengal War

The Bengal War, also called the second Anglo-Mughal war, was waged by the Mughal Empire in order to to expel the British East India Company (EIC) from Bengal Subah. Hostilities began in 1763 and ended in 1765.

Background
Mughal Emperor Farrukhsiyar in 1717 granted the EIC the right to trade within Bengal coupled with some exemptions for taxation. In the eyes of the Company, this decree granted it sovereignty, a right to trade undisturbed by the imperial powers. The EIC's opinion was that the emperor thus devolved its power and became a mere "official".

While the last independent Nawab of Bengal, Siraj ud-Daulah was concerned with the British claims of absolute sovereignty, EIC was only one part of his problems. Siraj, while trying to have an alliance with France, was also keeping the line of negotiation with Britain open. Siraj's successor, Mir Qasim (1760-1764), was the one seeing the advance of EIC as an existential threat and attempted to rebuild a smaller state in West Bengal where the private merchants would be excluded. This defiance eventually led to the war.

Hostilities
EIC agent William Ellis with a small detachment captured Patna by surprise. In a 1st battle of Patna on 25 June 1763, Bengali troops led by an Armenian mercenary Maskarian drove the British out of Patna, captured and held in captivity most of them.

After a destruction of British forces in the 1st battle at Patna, Mir Qasim's forces faced the British column headed by Major Thomas Adams intent on restoring Mir Jafar as a Nawab of Bengal. In a battle near the Katwa fortress on 19 July 1763 Adams' forces were victorious, Qasim's general, Mohammed Taki Shah, was killed.

Mir Qasim set up his defenses near Jangipur on Sooty on the plain of Giria. British forces under Major Thomas Adams attacked on 2 August 1763 and, after a bloody battle, forced Mir Quasim to retreat to Udaynala.

Mir Qasim was defeated again at Udaynala, where the British headed by Major Thomas Adams successfully stormed a well-defended Ganges gorge downstream of Rajmahal on 5 September 1763. After inflicting heavy losses at the gorge, Adams captured Monghyr.

After Udaynala, Mir Qasim killed the British soldiers captured in the 1st battle of Patna. Major Thomas Adams besieged Patna and captured the town in the 2nd battle of Patna on 6 November 1763 that saw heavy losses in the Bengali army.

Mir Qasim forged an alliance against the East India Company with Shah Alam and Shuja-ud-Daula.

On 3 May 1764 British EIC forces under the command of Colonel John Carnac were victorious in a 3rd battle at Patna against the Nawab of Oudh Shuja-ud-Daula. The British occupied defensive positions outside of Patna and caused heavy losses for the attacking Shuja's forces. After repulsing the attack, Carnac decided against a pursuit, but heavy rains caused Nawab's retreat a month later.

Battle of Buxar
On 23 October 1764, following the 3rd Patna battle, British forces under the command of Major Hector Munro, despite their numeric inferiority, carried a decisive victory over Indian allies at Buxar, west of Patna. Emperor surrendered to the British on the next day. Bengal became British.

After the battle of Buxar, Mir Qasim's and Shujah-ud-Daula's forces retreated into Doab with Major John Carnac in pursuit. They managed to join forces with Marathas headed by Malhar Rao Holkar. On May 1765 the British successfully used artillery against the Marathas. After the rout, Mulhar Rao fled to Kalpi, Mir Qasim sued for peace.

Shah Alam II managed to capture and hold Bihar. In 1764,

John Caillaud had set three official seals to document expressing an intent to kill Shah Alam II, while he had the Mughal Crown Prince, allegations that Caillaud would later strongly deny.

Aftermath
As a result of the war, the EIC became an indispensable military and fiscal instrument for the Mughal Emperor who was relying on the Company's military protection and financial means. While becoming effectively a sovereign in Bengal and Northern India by controlling the Bengal diwani in exchange for a fixed payment, the company was saddled with a large cost that EIC was forced to continue carrying due to commercial and political reasons. The document granting the revenues to the EIC was treated as a proto-constitution, a "Magna Carta".

The EIC waged a campaign to overthrow Shuja-ud-Daula.

The end of war signified the beginning of direct British rule in Bengal.