Hercule Poirot available to solve mysteries at an English country house. At the time of Christie's writing, it was considered patriotic to express sympathy towards the Belgians, since the invasion of their country had constituted Britain's "casus belli" for entering World War I, and British wartime propaganda emphasised the "Rape of Belgium". Poirot first appeared in "The Mysterious Affair at Styles" (published in 1920) and exited in "Curtain" (published in 1975). Following the latter, Poirot was the only fictional character to receive an obituary on the front page of "The New York Times". By 1930, Agatha Christie found Poirot "insufferable", and, by
Agatha Christie vault for over thirty years and were released for publication by Christie only at the end of her life, when she realised that she could not write any more novels. These publications came on the heels of the success of the film version of "Murder on the Orient Express" in 1974. Christie became increasingly tired of Poirot, much as Sir Arthur Conan Doyle had grown weary of his character Sherlock Holmes. By the end of the 1930s, Christie wrote in her diary that she was finding Poirot "insufferable", and by the 1960s she felt that he was "an egocentric creep".