George and Madras were captured by the French under General La Bourdonnais, the Governor of Mauritius, who plundered the town and its outlying villages. The British regained control in 1749 through the Treaty of Aix-la-Chapelle and strengthened the town's fortress wall to withstand further attacks from the French and Hyder Ali, the Sultan of Mysore. They resisted a French siege attempt in 1759. In 1769 the city was threatened by Mysore and the British were defeated by Hyder Ali, after which the Treaty of Madras ended the war. By the 18th century, the British had conquered most of the region around Tamil Nadu and the northern modern–day states of Andhra Pradesh and Karnataka, establishing the Madras Presidency with Madras as the capital. Gradually, the city grew into a major naval base and became the central administrative centre for the British in South India. The city served as the baseline for the Great Trigonometrical Survey of India started on 10 April 1802. With the advent of railways in India in the 19th century, the thriving urban centre was connected to other important cities such as Bombay and Calcutta, promoting increased communication and trade with the hinterland. Sir Arthur Lawley was Governor of Madras from 1906 to 1911 and promoted modern agriculture, industry, railways, education, the arts and more democratic governance. The Governor lived in Government House, Fort St George, and had a country home at Guindy, with access to a golf course, hockey pitches, riding stables and the Guindy Horse Racing Track. In the First World War as Red Cross Commissioner in Mesopotamia, he looked after the welfare of Indian soldiers. Madras was the only Indian city to be attacked by the Central Powers during World War I, when an oil depot was shelled by the German light cruiser on 22 September 1914, as it raided shipping lanes in the Indian Ocean, causing disruption to shipping. After India gained its independence in 1947, the city became the capital of Madras State, which was renamed as Tamil Nadu in 1969. The violent agitations of 1965 against the compulsory imposition of Hindi and in support of English in India in the state marked a major shift in the political dynamics of the city and eventually it had a big impact on the whole state. Because of Madras and its people, English was not abolished as an official language, and remains an official language