 In 1802, the diocese was united with that of Chambéry.At the Congress of Vienna of 1814–15, the territory of Geneva was extended to cover 15 Savoyard and six French parishes, with more than 16,000 Catholics; at the same time it was admitted to the Swiss Confederation.The Congress expressly provided—and the same proviso was included in the Treaty of Turin (16 March 1816)—that in these territories transferred to Geneva the Catholic religion was to be protected, and that no changes were to be made in existing conditions without the approval of the Holy See.