citadel built by the English East India Company in Madras, India, later becoming the British capital in South India. The fort, named in honour of Britain's patron saint, is well preserved by the state of Tamil Nadu (formerly Madras).

The English East India Company's original trading station in South India was at Masulipatam, established in 1611. It was moved to Madras, where permission to build a fort was obtained from the Raja of Chandragiri in 1639, mainly because it was nearer the weaving centres from which the company obtained goods for export to Persia and the East Indies. It became the headquarters of the company in South India in 1641, and it was the first company settlement in India to be fortified. In 1746 it was captured briefly by the French; on recovery, in 1748, it was largely rebuilt, enabling the British to defend it successfully against the French in 1758–59. The fort was twice threatened by Hyder Ali (1769 and 1780). Thereafter it was largely remodeled to become the centre of the British South Indian administration.