Died in an accident aged 25
Buried in the churchyard of All Saint’s Church, Steep, Hampshire.

Oswald was born in London to Victor and Eldred Horsley.

Victor, the son of a Royal Academician, became a doctor. He was an early pioneer of neuro-surgery and was appointed Professor of Clinical Surgery at University College London, in 1899. He was a keen Liberal and a champion of many causes. One of his life's crusades was the temperance movement having observed that many injuries admitted to the hospital, were due to alcohol. He was also a supporter of Women's Suffrage, and was an opponent of tobacco as well as alcohol. 

He was knighted and at the outbreak of the war, requested active duty on the Western Front, but was posted in 1915, as a colonel and Director of Surgery of the British Army Medical Service in Egypt and the Dardanelles. 

In 1916, he volunteered for field surgery duty in Mesopotamia, where he died from heat stroke in Amarah Iraq, on 16 July 1916, aged 59.

Oswald and his brother Siward were educated at Bedales. Oswald came up to Christ Church in 1912. He joined the Gordon Highlanders on 15 December 1914 and was seconded to the RAF. Mentioned in Dispatches France 1915.

He was awarded the Military Cross, gazetted 2 October 1916:
“For conspicuous gallantry and devotion to duty. 16 July 1916 he has brought down three hostile machines, and of two others which he engaged, one he fought to within a distance of 200 feet from the ground, forcing it to land, the second spinning down to the ground out of control, he being unable to observe it crash owing to the presence of other hostile machines. He has carried out accurate and valuable reconnaissances and has set a magnificent example of determined gallantry and skill whilst leading low flying and bombing patrols.”
Bar awarded 22 June 1918.

He was killed, accidentally, on 19 August 1918. Probate was granted on 21 November 1918 to Pamela Comfrey Robinson [his sister] wife of Edward Stanley Gotch Robinson. He left £1025-7s-6d.

Siward died on 25 December 1920 from wounds received in 1915 at Neuve Chappelle and is also buried at Steep.

Sir Victor’s Papers were sorted by his wife after his death to provide material for the authorised biography by Stephen Paget, published in 1919. The bulk of the Papers were presented to University College, London in 1976 by their daughter, Lady Robinson. Her daughter, Mrs Penelope Heseltine, deposited the remainder in 1987. Letters from Oswald are in the Papers of Lady Allen of Hurtwood deposited with the University of Warwick.