The murder of a national leader is usually called an "assassination," and the person who carries it out is an "assassin." Some famous (or infamous) assassins in history have been John Wilkes Booth, who killed President Abraham Lincoln, Gavrilo Princip, a Serbian assassin who murdered Austrian Archduke Franz Ferdinand, helping to spark World War I, and Lee Harvey Oswald, who shot and killed President John F. Kennedy. Another word for the killing of a national leader with historical significance is "regicide." This word specifically refers to the killing of a monarch. One example of a "regicide" is the execution of King Charles I of England at the end of the English Civil War. The men responsible called themselves "tyrrannicides," which means "killers of tyrants," and some of them were themselves executed when the English monarchy returned to power in 1660. In England, in fact, the word specifically refers to Charles's executioners, who like the men who sentenced King Louis XVI to death in France at the height of the French Revolution, they claimed legal authority to do so.