Peter Gordon once worked in the Foreign Office, where he befriended Patrick Crawley, whose father was the heir to Downton Abbey and the title Earl of Grantham. Peter later immigrated to Montreal in 1913, a year after Patrick drowned on the Titanic.
During World War I, when a wounded officer claimed to be the presumed dead Patrick, it was thought by some that he might actually be Peter, which would explain how the officer knew certain details of the family. Edith thought they might then try to track Peter down.
Shortly after however, the officer disappeared, and it was never proven if he was Patrick Crawley, Peter Gordon, or someone else entirely.