George I of Greece was King of Greece from 1863 to 1913. Originally a Danish prince, when only 17 years old he was elected King by the Greek National Assembly, which had deposed the former King Otto. His nomination was suggested and supported by the three Great Powers (United Kingdom of Great Britain and Ireland, Second French Empire and the Russian Empire). As the first monarch of the new Greek dynasty, his 50-year reign (the longest in modern Greek history) was characterized by territorial gains as Greece established its place in pre-World War I Europe. Two weeks short of the fiftieth anniversary of his accession, and during the First Balkan War, he was assassinated. In sharp contrast to his reign, the reigns of his successors would prove short and insecure.