The decoration of sequined fireworks on this evening dress, which was worn by the Countess Madeleine de Montgomery to Lady Mendl's 75th birthday party in 1939, is a fitting climax to le beau monde of the 1930s. For, as Janet Flanner wrote in Paris Was Yesterday, "In the summer of 1939 fêtes were held and fireworks were fired, for the beau monde's … pleasure. The Grand Prix race at Longchamps was held at night under floodlights: a splendid affair attended by the most elegant figures of Paris society … But by then the Thirties were at the point of death. Their executioner was Adolf Hitler. On September 1, 1939, those of us in Paris who were listening to the early-morning news broadcast heard Herr Hitler announce in German, at once translated into French, that 'as of this morning we are at war with Poland.' The Thirties were over. World War II had begun."