Emperor

Emperor or empress was a title given to a ruler of an empire or any other imperial state. An empress referred to a woman who either ruled an empire or was the head of state of an empire. This term could also refer to a woman who was the consort of a reigning emperor.

Many civilizations, including the Klingons, Romulans, and Andorians, have used imperial titles at various points in their history; however, few appear to have been ruled by emperors during the period when they came into contact with Humans. The Romulan Star Empire was ruled by an emperor during a point in its past, but political power rests with the Romulan Senate and the praetor. Q, however, once told Captain Kathryn Janeway that he could have mated with the Romulan empress for the purpose of creating a child, but that he instead chose his favorite Human, "Kathy". 

In the mirror universe, emperors, possibly sometimes called caesars, ruled the Terran Empire in 2155 and 2267. In 2155, $𝜇$ declared herself empress of the Terran Empire after seizing control of the USS Defiant (NCC-1764) and ordering Starfleet's unconditional surrender. $𝜇$ suggested that Captain $𝜇$ might aspire to become caesar. . In addition, the Klingon emperor of the $𝜇$ ruled the Klingon-Cardassian Alliance, but real power was in the hands of the Regent. 

On the planet 892-IV, a world identical to the Roman Empire had developed which was, as of 2268, ruled by emperors who could trace their lines back 2,000 years to their own Julius and Augustus Caesars. 

Similarly, the Klingons were ruled by an emperor until the mid-21st century, when power passed to the chancellor and the High Council. In 2369, a clone of Kahless the Unforgettable assumed the title of emperor, with merely symbolic power. 

After negotiating Cardassia's annexation into the Dominion in 2373, Dukat effectively became the emperor of the Cardassian people, though still a servant of the Founders. However, he chose to maintain his rank of gul as opposed to legate because he felt it was more "hands on", and Emperor, President, First Minister and Emissary seemed too "pretentious". 

List of emperors and empresses

 * Emperor of the Qin dynasty in China (3rd century BC)
 * Emperor of the Terran Empire (2155)
 * Empress $𝜇$ of the Terran Empire (2155)
 * Emperor of the Terran Empire (2267)
 * Emperor of the Roman Empire (1st century)
 * Emperor of 892-IV (2268)
 * Empress of the Romulan Star Empire
 * Emperor of the Klingon-Cardassian Alliance (2370)
 * Emperor Caesar Augustus of the Roman Empire
 * Emperor Darmok of Kanda IV (seventh dynasty)
 * Emperor Kahless of the Klingon Empire (2369)
 * Emperor Kahless the Unforgettable of the Klingon Empire (9th century)
 * Emperor Mur'Eq of the Klingon Empire
 * Emperor Reclaw of the Klingon Empire (Klingon Second Dynasty)
 * Emperor Reclaw of the Klingon Empire (Klingon Third Dynasty)
 * Emperor Sompek of the Klingon Empire

Imperator Empereur Emperor