Nikolay Konstantinovich, who had lived a dissipated life and had revolutionary ideas, had stolen three valuable diamonds from an icon in Alexandra's private bedroom, aided by his mistress, an American courtesan. Alexandra's twenty-four-year-old son was found guilty, declared insane, and banished for life to Central Asia. Alexandra suffered another bitter blow when in 1879, her youngest son, Vyacheslav, died unexpectedly from a brain haemorrhage. Husband's illness and death In June 1889, Alexandra’s 18-year-old granddaughter, Princess Alexandra of Greece, returned to Russia to marry Grand Duke Paul, who was the younger brother of Tsar Alexander III. Towards the end of the wedding celebrations, Konstantin suffered a stroke. This was followed in August 1889 by a severe stroke, which left him unable to walk or speak. For the remaining three years of his life Konstantin lived with his wife in her favourite palace Pavlovsk, having a wing of the building to himself. He was confined to a bath chair, and Alexandra saw to it that Konstantin was denied contact with his mistress and illegitimate offspring. Alexandra’s grandson, Christopher of Greece, wrote in his memoirs that Konstantin became so frustrated with being under Alexandra’s control that he one day grabbed her by the hair and beat her with his stick. Seeing as Christopher would have only been four years old at the time of Konstantin’s death, it is difficult to know the full truth of this story. Despite his illness, Konstantin tried to amuse himself as best he could. His grand-nephew Cyril Vladimirovich remembered skating parties at Pavlovsk, where Konstantin would watch from his sledge, and how he always "smelt of cigars". Cyril found Alexandra a formidable woman, with her "high pitched voice....driving about in an open carriage with a kind of awning over it, which could be opened and closed like an umbrella. I have never seen anything quite the same anywhere else, and think that she was the only person in the world who had such an ingenious cover to her carriage". When Konstantin died, in January 1892, Alexandra arranged for his mistress Anna to visit Pavlovsk and pray at Konstantin’s bedside. Archives Alexandra's letters to her daughter, Queen Olga of Greece, between 1867 and 1877 are preserved in the "Aleksandra Iosifovna letters to Queen Olga of Greece" collection in the Hoover Institution Archives (Stanford, California, USA). Alexandra's letters to Princess Florestine of Monaco, written between 1873 and 1879, are preserved