 Lawrence's account the Arab Revolt against the Ottoman Empire during World War I.

McMahon was the son of Lieutenant-General Charles Alexander McMahon, FRS, FGS (1830–1904), a geologist and Commissioner of both Lahore and Hisar in Punjab, India, and who, like his father Captain Alexander McMahon (born 1791, Kilrea, County Londonderry, Ireland) had been an officer with the East India Company.The McMahons are the Gaelic clan of Mac Mathghamhna who had come originally from the medieval Irish kingdom of Airgíalla or Oriel in South Ulster/North Leinster, where they reigned from around 1250 until about 1600.Sir Henry McMahon's own family had settled in the Downpatrick area of County Down before his great-grandfather, The Rev.