A British force besieged the French-controlled port of Pondicherry (now Puducherry) in August 1778, which capitulated after ten weeks of siege.

Following the colonial victory at Saratoga in October 1777, France decided to declare war on Great Britain as an ally to the United States.

Word first reached the French Indian colony of Pondicherry in July 1778 that France and Britain had recalled their ambassadors, a sign that war was imminent.

The British colonies had already received orders to seize the French possessions in India and begun military preparations.

Attempts to significantly improve its defences after the last round of battles in the Seven Years' War were frustrated by political infighting in the French colonial administration.

Key gates were blocked, stockades and gun batteries were constructed along the shore, and anything that might give cover to the British on their advance on the defences was removed or destroyed.

[Note 1] The British colonial administration in Madras placed General Hector Munro in command of an army of nearly 20,000 men, which began arriving within a few miles of Pondicherry on 8 August.

In a largely inconsequential two-hour engagement in which Tronjoli was wounded, the French fleet drove Vernon away on 10 August.

[5][Note 2] The loss of parity between the navies was partially made up by the arrival at Pondicherry of the 26-gun frigate Elizabeth, another private ship that had been pressed into service in the French fleet.

The French fleet, although it had been augmented by Elizabeth, was forced to leave Le Brisson in the harbour due to damage sustained in the first engagement, and was thus at a disadvantage.

Bellecombe was surprised and dismayed to learn on 2 September that Tronjoli had sailed for Île de France, leaving Elizabeth and La Pourvoyeuse behind.

By 24 September breaches were beginning to show in the bastions under attack, and by 6 October the British trenches had reached the inner ditches, with additional gun batteries doing significant damage along the entire French works.