William George Sydney Cadogan was born 31 January 1879 in Chelsea, London, England, United Kingdom to George Henry Cadogan, 5th Earl Cadogan (1840-1915) and Beatrix Jane Craven (1844-1907) and died 12 November 1914 First Battle of Ypres of killed in action.
LONDON, November 13. Mjr. William Cadogan, who was equerry to the Prince of Wales, has been killed in action on the Continent.
The Hon. William George Sydney Cadogan, M.V.O., was born in 1879, and was a son of the fifth Earl of Cadogan. He was educated at Sandhurst. He served in the South African war in 1900, and was a major in the 10th Hussars. During the tour by the Prince of Wales in India in 1905-6 Mjr. Cadogan acted as A.D.C.