Tsar Nicholas II's love letters to his secret mistress Catherine Dolgorukov have sold as part of Profiles in History's auction of Property of a Distinguished American Collector Part II.
Crossing the block in California last night (May 30), the letters realised $80,000, meeting their top estimate.
Tsar Alexander II (1818-1881), also known as Alexander the Liberator, had married Empress Marie Alexandrovna in 1841.
The empress had given him six children, but by the time they ascended the imperial throne in 1855, her health had declined and she knew that the emperor was "tiring of her".
He moved through a series of love affairs until 1864, when Catherine Michailovna (then Princess Dolgorukov) attracted his attention.
The young princess, then a student, resisted his advances for two years, before they finally consummated their relationship in 1866.
Alexander then moved his new mistress to his court, giving her the position of the empress' maid of honour. The empress died in 1880, and just a month and a half later, the emperor and Catherine married in a secret ceremony, with Catherine given the title of Princess Yurievskaya.
Less than one year later, Alexander was dead, killed by a terrorist bomb. Princess Yurievskaya soon moved to France, where she lived until her death in 1922.
Also selling well in the auction was an autographed letter from Ludwig van Beethoven, which was addressed to opera singer Friedrich Sebastian Mayer just days before the premiere of Beethoven's opera Fidelio in 1805.
The letter sold for $80,000, making a 33.3% increase on its $60,000 high estimate.
Outside of the astonishing array of letters and ephemera was an extraordinary photo album recording Adolph Hitler's second visit to Italy and Mussolini's first to Germany.
Leather bound and featuring a stunning array of crisp, personal shots of the two tyrannical leaders, it sold for $30,000.
View our rare signed letters for sale.