By the early 18th century, the British East India Company had a strong presence in India with the three main stations of Fort St. George in Madras, Fort William in Calcutta and Bombay Castle in western India. These stations were independent presidencies governed by a President and a council, appointed by the court of England . The British adopted a policy of allying themselves with various princes and Nawabs, promosing security against usurpers and rebels.The Nawabs often gave them concessions in return for the security. By then, all rivalry had also ceased between the English East India Company under Louis XIV and had two important stations in India - Chandernagar in Bengal and Pondichery on the Carnatic coast, both governed by the presidency of Pondichery. The French were a late comer in Indian trade, but they quickly established themselves in India and were poised to overtake Britain fot control.
The war of the Austrian Succession marked the beginning of the power struggle between Britain and France and of European military ascendancy and political intervention in the Indian subcontinent. In Sept. 1746, Mahe de La Bourdonnais landed off Madras with a naval squadron and laid siege to the port city. The defences of Madras were weak and the garrison sustained a bombardment of three days before surrendering. There was disagreement between Bourdonnais and Joseph francois Dupleix, the Governor general of the Indian possessions of the French Govt. At the same time, the Nawab of Carnatic Anwaruddin Muhammed Khan intervened in support of the British and the combined forces and a battle lasted for Pondichery for 31 days and the battle ended with an agreement in 1748 with Madras back to British in return for Louisbourg and Cape Breton Island in North America.
In the meantime Alivardi Khan ascended to the throne of the nawab of Bengal..