Poirot's Family and childhood

It is difficult to draw any concrete conclusions about Poirot's family due to the fact that Poirot often supplies false or misleading information about himself or his background in order to assist him in obtaining information relevant to a particular case. In chapter 21 of The Murder of Roger Ackroyd, for example, we learn that he has been talking about a mentally disabled nephew: this proves to be a ruse so that he can find out about homes for the mentally unfit … but that does not mean that Poirot does not have such a nephew. In Dumb Witness, he regales us with stories of his elderly invalid mother as a pretence to investigate the local nurses. In The Big Four Hastings believes that he meets Achille Poirot who (in an apparent parody of Mycroft Holmes) is evidently his smarter brother. On this occasion, Achille is almost certainly Poirot himself in disguise (Poirot speaks in Chapter 18 of having sent Achille "back to the land of myths"), but this does not conclusively demonstrate that Poirot does not have a brother, or even a brother called Achille. Any evidence regarding Poirot for which Poirot himself is the source is therefore most unreliable.

Poirot was apparently born in Spa, Belgium and, based on the conjecture that he was thirty at the time of his retirement from the Belgian police force at the time of the outbreak of the First World War, it is suggested that he was born in the mid 1880s. This is all extremely vague, as Poirot is thought to be an old man in his dotage even in the early Poirot novels, and in An Autobiography Christie admitted that she already imagined him to be an old man in 1920. (At the time, of course, she had no idea she would be going on writing Poirot books for many decades to come.) Much of the suggested dating for Poirot's age is therefore post-rationalisation on the part of those attempting to make sense of his extraordinarily long career.

Poirot is a Roman Catholic by birth, and retains a strong sense of Catholic morality later in life. Not much is known of Poirot’s childhood other than he once claimed in Three Act Tragedy to have been from a large family with little wealth. In Taken at the Flood, he further claimed to have been raised and educated by nuns, raising the possibility that he (and any siblings) were orphaned.