Russian royalty, a member of the Romanov family as the sixth son and youngest child of Emperor Alexander II of Russia by his first wife, Empress Maria Alexandrovna. He was a brother of Emperor Alexander III and uncle of Nicholas II, Russia’s last monarch.
He entered the Russian Army, was a general in the Cavalry and adjutant general to his brother Emperor Alexander III, and a Knight of the Order of St. Andrew. In 1889, he married Princess Alexandra of Greece, his paternal first cousin once removed. The couple had a daughter and a son, but Alexandra died during the birth of their second child. In his widowhood, Grand Duke Paul began a relationship with Olga Valerianovna Karnovich, a married woman with three children. After obtaining a divorce for Olga and in defiance of a strong family opposition, Grand Duke Paul married her in October 1902. As he contracted a morganatic marriage with a divorcée in defiance of the Tsar’s prohibition, Grand Duke Paul was banished from living in Russia and deprived of his titles and privileges. Between 1902 and 1914, he lived in exile in Paris with his second wife, who gave him three children. In the spring of 1914, he settled back in Russia with his second family.
With the outbreak of World War I, Grand Duke Paul was appointed in command of the first corps of the Imperial Guard. Afflicted with ill health, he served only intermittently. During the last days of the Tsarist period, he was one of the few members of the Romanov family who remained close to Tsar Nicholas II and his wife, Alexandra Feodorovna. It fell upon Grand Duke Paul to inform Alexandra of Nicholas II’s abdication.
After the fall of the Russian monarchy, Grand Duke Paul initially remained at his palace in Tsarskoe Selo during the period of the provisional government. With the Bolsheviks ascending to power, his palace was expropriated, and eventually he was arrested and sent to prison. In declining health, he was shot by the Bolsheviks with other Romanov relatives in the courtyard of the Peter and Paul Fortress on 28 January 1919, aged 58, and his remains were thrown into a common grave.
Link to Wikipedia biography