During the "secretive" period, Diderot accomplished a well-known work of subterfuge. The title pages of volumes 1 through 7, published between 1751 and 1757, claimed Paris as the place of publication. However, the title pages of the subsequent text volumes, 8 through 17, published together in 1765, show "Neufchastel" as the place of publication. Neuchâtel is safely across the French border in what is now part of Switzerland but which was then an independent principality, where official production of the "Encyclopédie" was secure from interference by agents of the French state. In particular, regime opponents of the "Encyclopédie" could not seize the production plates for the "Encyclopédie" in Paris because those printing plates ostensibly existed only in Switzerland. Meanwhile, the actual production of volumes 8 through 17 quietly continued in Paris.