The Battle of Waterloo in 1815 was fought between a Frenchman who wasn't really French and an Englishman who wasn't really English.
Napoleon was born in Corsica in 1769. The island had long been subject to the Republic of Genoa, but after a protracted struggle for independence, which attracted the admiration of Rousseau and James Boswell amongst others, Corsica was sold to France by the Genoese in 1768. The name "Napoleon" was unknown in France before his time. To this day, Corsicans are seen as being quite different from other French citizens.
The future Duke of Wellington was also born in 1769, in his case in Dublin. His father was an Irish nobleman and he himself sat in the Irish Parliament before the Act of Union with Britain. When it was suggested to Wellington that he was therefore, in fact, Irish, he replied, "Sir, being born in a stable does not make you a horse!"
This kind of "displaced nationalism" is not unusual amongst great national leaders. George Orwell once wrote that, "One quite commonly finds that great national leaders, or the founders of nationalist movements, do not even belong to the country they have glorified. Sometimes they are outright foreigners, or more often they come from peripheral areas where nationality is doubtful" ("Notes on Nationalism": 1945). As well as the obvious examples, Orwell cited Lord Beaverbrook, a Canadian who spent most of his life in Britain as a strongly nationalist newspaper magnate and political intriguer, and Benjamin Disraeli, a maverick Conservative Prime Minister who invented the title "Empress of India" for Queen Victoria, but was at the same time immensely proud of his Jewish heritage.
The two greatest European dictators of the twentieth century certainly fit Orwell's description. Most people know that Adolf Hitler, although obsessed with the notion of a German race, was born a citizen of the Austrian Empire, whose multi-racial character he despised. Although he joined the German army in 1914, he did not bother to take up German citizenship until 1932. Stalin was a Georgian, by name Josef Vissarionovich Djugashvili, who only learnt to speak Russian at school, but who in 1923 alarmed even Lenin by the brutality with which he compelled his Georgian homeland to be incorporated into the Soviet Union. (Some Georgians have maintained that Stalin was not a true Georgian at all, but was half Ossetian!). Then again, Hendrik Verwoerd, who set up the full apartheid system in South Africa after the Second World War, was not a true Boer, having been born in Holland. Eamon de Valera, the Irish leader who plunged his country into civil war rather than accept the compromise treaty of 1921, was born in New York of a Cuban-Spanish father; hence his very un-Irish surname. In the great crisis over Irish Home Rule before the First World War, the resistance of Ulster was led by Sir Edward Carson, who was not an Ulsterman but a barrister most famous for his demolition of Oscar Wilde in 1895; strongly supported by the Conservative leader Andrew Bonar Law, who was born in Canada and later became the only British Prime Minister not to have been born in the U.K.
The last word on this subject must go to David Lloyd George, Prime Minister during the First World War and at the Versailles Peace Conference, and probably the most famous Welshman of all time. He was actually born in Manchester, but as he told his son, "Nationality has nothing to do with geography: it is a state of mind".