Emperors of Traditional Empires
Ancient empires::
Persian Empire (559 BC–330 BC)
Empire of Alexander the Great (334 BC–281 BC)
Mauryan Empire (321 BC–185 BC)
China (Empire 221 BC–1911)
Roman Empire (27 BC–476)


Middle Ages::
Western and Byzantine traditions
Byzantine Empire (395–1453)
Byzantine Empire (395–1453)
Bulgaria (Empire 913–1422)
Serbia (Empire 1345–1371)
Muscovy (Empire 1480–1721)


Newer Empires::
Austrian Empire, 1804–1867 and the Austro-Hungarian Empire, 1867–1918
British Empire de jure 1877 - 1947
Empire of Brazil (Peter I, 1822–1831 and Peter II, 1831–1889)
France:
First French Empire (Napoleon I, 1804–1814, 1815)
Second French Empire (Napoleon III, 1852–1870)
German Empire (under the Hohenzollerns, 1871–1918)
Russian Empire (under the Romanovs, 1721–1917)
Korean Empire (Gojong, 1897–1907 and Sunjong, 1907–1910)


Emperors of short-lived 'empires':
Emperor Jacques I of the Empire of Haiti (1804–1806)
Emperor Jacques I of the Empire of Haiti (1804–1806)
Emperor Faustin I of the Empire of Haiti (1847–1859)
Emperor Maximilian of the second Mexican Empire (1864–1867)
Emperor Sylvain I of the Empire of Haiti (1868–1870, not confirmed)
Emperor Hongxian of China (1915–1916)
Emperor Bokassa I of the Central African Empire (1976–1979)