The Traitor is firmly grounded in fact. The majority of the people referred to in the novel took part in the actions described. Many of the conversations are based on diary entries, memoranda and letters subsequently published by the main protagonists. The principal exception to this is the character of Major Lionel Samson. When he first appears, Samson is, as he was in fact at the time, the British Military Consul at the siege of Adrianople in 1913. By 1915 he was, in real life, in charge of the allied espionage network based in Athens. However, between these two dates, all actions ascribed to him in The Traitor are fictional.