 He was the youngest brother of T. E. Lawrence ("Lawrence of Arabia") and his literary executor.Arnold Lawrence was born at 2 Polstead Road, Oxford, on 2 May 1900, the youngest of five sons born to Thomas Chapman (who became, in 1914, Sir Thomas Chapman, 7th Baronet), an Anglo-Irish nobleman from County Westmeath, and Sarah Junner (1861–1959).The couple were unmarried but took the names "Thomas Robert Lawrence" and "Sarah Lawrence".