In 1867, Offenbach had his greatest success. The premiere of "La Grande-Duchesse de Gérolstein", a satire on militarism, took place two days after the opening of the Paris Exhibition, an even greater international draw than the 1855 exhibition which had helped him launch his composing career. The Parisian public and foreign visitors flocked to the new operetta. Sovereigns who saw the piece included the King of Prussia accompanied by his chief minister, Otto von Bismarck. Halévy, with his experience as a senior civil servant, saw more clearly than most the looming threat from Prussia; he wrote in his diary, "Bismarck is helping to double our takings. This time it's war we're laughing at, and war is at our gates." "La Grande-Duchesse de Gérolstein" was followed quickly by a series of successful pieces: "Robinson Crusoé", "Geneviève de Brabant" (revised version; both 1867), "Le château à Toto", "Le pont des soupirs" (revised version) and "L'île de Tulipatan" (all in 1868).