Nicholas became ill in 1865 on a tour of southern Europe. It was eventually determined that he was suffering from cerebro-spinal meningitis, and it was speculated that his illness was caused by a previous accident in a wrestling match, in which Nicholas participated and was thrown down. He continued to decline, and he died on 24 April 1865, at the Villa Bermont in Nice, France. It is believed that on his deathbed, Nicholas expressed the wish that his fiancée become the bride of his younger brother and successor Tsesarevich, Alexander, and in 1866, the future Alexander III married Queen Alexandra's younger sister Princess Dagmar of Denmark. She was the second daughter of King Christian IX of Denmark and Louise of Hesse-Kassel and became Marie Feodorovna, mother of Nicholas II.