Paul I of Russia
Paul I (; "Pavel Petrovich") ( – ) reigned as Emperor of Russia between 1796 and 1801. Officially, he was the only son of Peter III and Catherine the Great, though Catherine hinted that he was fathered by her lover Sergei Saltykov, who also had Romanov blood, being a descendant of the first Romanov tsar's sister, Tatiana Feodorovna Romanova.
Saint Michael's Castle
Paul I was assassinated only 40 nights after he moved into his newly built castle. He was murdered on 12 March 1801, in his own bedroom, by a group of dismissed officers headed by General Bennigsen. The conspirators forced him to a table, and tried to compel him to sign his abdication. Paul offered some resistance, and one of the assassins struck him with a sword, and he was then strangled and trampled to death. He was succeeded by his son, Emperor Alexander I, who was actually in the palace at the time and was informed of his accession by General Nicholas Zubov, one of the assassins.