As Waugh's disillusion with the war intensified, his next step in defence of embattled Christendom logically took him to its invisible heart, the soul of the individual. In a later essay on Saint Helena, he identifies the conviction that underlies both Brideshead Revisited, and the subsequent war trilogy:

Waugh would have liked to achieve something conspicuous as a soldier. Even his loudest detractors freely admit his bravery. He was perfectly ready and seriously expected to sacrifice his life fighting for the survival of Christianity. For him personally, the Second World War, even more than its Abyssinian overture, was ‘a disappointing war’. His assignments after the fall of Crete were humdrum. In 1943 a heaven-sent accident during a practice parachute drop – literally a happy fall – brought him injury, sick-leave, and finally official permission for three months’ unpaid leave in order to write Brideshead Revisited. His magnum opus. Something which only he could do.

In his letter applying for leaveWaugh said his projected novel would not deal directly with the war; nor could it be pretended to have any propaganda value, but ‘it may cause innocent amusement and relaxation’ to its readers (D 557, n.1). Most readers respond innocently and pleasurably to Ryder's two love stories, for Sebastian, and his sister Julia. Contemporaries were also quick to identify the originals Waugh denied in his prefatory Author's note: ‘I am not I: thou art not he or she: they are not they.’ As Nancy Mitford wrote to Waugh, everyone was saying that Lord Marchmain was the Seventh Earl Beauchamp and the Flytes were his friends, the Lygon children. However, this easy identification ignores a central difference between the two families. Lord Beauchamp had to leave England because of his homosexuality; Lord Marchmain took up voluntary exile because of his adultery. Lady Marchmain's Catholicism makes divorce impossible; in Marchmain's Venetian palazzo and continental watering-places her estranged husband, a lapsed Catholic, maintains a ménage of quiet propriety with his mistress, Cara.