An Emperor is nominally a monarch and sovereign ruler of an Empire or any other imperial realm. Emperors are generally recognized to be above kings in honour. They may be obtain their position hereditarily, or by force, such as a coup d'état.

The English term for emperor is derived from the Latin imperator (literally, "one who prepares against"; loosely, "commander"). In German the title Kaiser is used and in Russian tsar or czar is used, both of which are derived from Caesar.

There is currently only one Emperor left in the world, the Emperor of Japan.

Imperator was originally a title used by the highest-ranking Roman commanders, roughly comparable to field marshal or commander-in-chief. Caesar was the family name of Gaius Julius Caesar (100 BC-44 BC), who never was an emperor himself but rather the last dictator of the Roman Republic. The name of Caesar lived on by adoption in the first Roman Emperor, Gaius Julius Caesar Octavianus (better known as Caesar Augustus). This was not a constitutional office but rather a complicated collection of offices, titles, and honours.

In China, Emperor was first introduced when Qin Shi Huangdi declared him as the first emperor. In Japan, a ruler in Yamato court was called "Tenno" and usually translated as emperor, though Japan is usually not considered an "empire" in the traditional sense except during the brief period of the Meiji, Taisho and early Showa emperors. In Japanese language, tenno is strictly distinguished from teiou who rules an empire--both are translated as emperor.

Sometimes, a retired emperor has actual power instead of the ruling emperor.

Countries which have been ruled by Emperors or Empresses:

Table of contents
1 Ancient Empires
2 Medieval Empires
3 Newer Empires
4 Emperors of short-lived "Empires"
5 Self-proclaimed "Emperors"
6 Fictional Empires
7 Unclassified

Ancient Empires

Medieval Empires

Newer Empires

Emperors of short-lived "Empires"

Self-proclaimed "Emperors"

Fictional Empires


  • Although the Emperor of Japan (1945- ) is classified as constitutional Monarch Emperor among political scientists, the constitution of Japan defines him only as a symbol of the nation and no law states his status as a political monarch or otherwise.