Hercule Poirot met his lifelong friend, Captain Arthur Hastings, and solved the first of his cases to be published, "The Mysterious Affair at Styles". It is clear that Hastings and Poirot are already friends when they meet in Chapter 2 of the novel, as Hastings tells Cynthia that he has not seen him for "some years". Particulars such as the date of 1916 for the case and that Hastings had met Poirot in Belgium, are given in "Curtain: Poirot's Last Case", Chapter 1. After that case, Poirot apparently came to the attention of the British secret service and undertook cases for the
Hercule Poirot (and poses as) an identical twin brother named Achille: however, this brother was mentioned again in "The Labours of Hercules". To this day Harold is not quite sure what made him suddenly pour out the whole story to a little man to whom he had only spoken a few minutes before. Poirot is also willing to appear more foreign or vain in an effort to make people underestimate him. He admits as much: It is true that I can speak the exact, the idiomatic English. But, my friend, to speak the broken English is an enormous asset. It leads people