The sieges took place after Thuljaji, the Rajah of Tanjore, provided fewer levies and money than the British had required him to and invaded lands claimed by the Arcot State.
From 1766 to 1769, the British East India Company, the Maratha Confederacy, and the Arcot State (also known as the Carnatics) waged a war against the Kingdom of Mysore, a nation led by Hyder Ali.
To fight Hyder's armies, the Anglo-Maratha-Carnatic alliance employed a large number of levied soldiers and mercenaries from various vassal and allied states.
It was also revealed that Thuljajil the Rajah of Tanjore, had been in communication with Hyder Ali; these actions earned the Raj the enmity of the British and the Arcots.
[2] Following the victory at Tanjore, the British army helped the Carnatics officially conquer the Marawar chiefs in 1772, whom the allies had recently liberated.