Greece was recognized by the Great Powers in 1828, having gained independence from the Ottoman Empire. In 1832, the Treaty of London established Greece as a monarchy, and Prince Otto of Bavaria, from the House of Wittelsbach, was chosen King of the Greeks. He was never fully accepted by the Greek people, despite nearly 30 years on the throne. Otto was deposed in 1862.
The Great Powers chose Prince Wilhelm of Denmark, the 17-year old son of King Christian IX, as the new monarch. He ruled as George I of the Hellenes. His descendants reigned, with a few interruptions, until 1973 Greece once again became a Republic and King Constantine II, the last Greek monarch, was deposed.
House of Wittelsbach: 1832 – 1862
- 1832-1862 Otto
House of Schleswig-Holstein-Sonderburg-Glücksburg: 1863 – 1973
- 1863-1913 George I
- 1913-1917 Constantine I
- 1917-1720 Alexander
- 1920-1922 Constantine I
- 1922-1924 George II
- 1935-1947 George II
- 1947-1964 Paul
- 1964-1973 Constantine II