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 of Roger Ackroyd". It has been said that the twelve cases related in "The Labours of Hercules" (1947) must refer to a different retirement, but the fact that Poirot specifically says that he intends to grow marrows indicates that these stories also take place before "Roger Ackroyd", and presumably Poirot closed his agency once he had completed them. There is specific mention in "The Capture of Cerberus" of the twenty-year gap between Poirot's previous meeting with Countess Rossakoff and this one. If the "Labours" precede the events in "Roger Ackroyd", then the Ackroyd case must have taken place around twenty