The Hermitage is a 
Russian event. It signifies the opening of the world famous Hermitage Museum.
It can happen at any time between 1852 and 1855. It has a mean time to happen of 5 months, which will decrease to 3.75 months after 1853 and again to 3.5 after 1854.
It has a single option: To the glory of the Czar! which gives 5 prestige. The ingame text says: The are collection in the Hermitage, built after plans of Leo van Klenze, opened in St. Petersburg. It made available to the public some of the finest and most precious pieces of art to be found in all of Russia.
Even if Russia becomes a democracy the option will still be 'To the glory of the Czar!'.