What is the difference between an Emperor and a King?

Question

I was at a loss when I was asked recently by my grand-daughter who is a school girl about the difference between Emperor and King. She asked me why Great Britain has King and Queen, while Germany and Russia had the Emperors, and France had both Kings and Emperors. All what I could tell her was, ‘you’d better study by yourself, don’t count on others.”

Being sorry for her, I checked dictionaries at hand, but was simply confounded.

For instance, OALD defines:

Emperor: the ruler of empire.

Empire: a group of countries that are controlled by one ruler / government.

King: the (male) ruler of an independent state / country that has a royal family.

Kingdom: a country ruled by a king (or queen).

The difference seems to be;

1. King has a royal family.
2. Empire is a group of countries (under one ruler).

But emperors have royal families as well, and Japan that has had the emperors for a millennium has been a single country (except the imperialism era of 1910–1945), and China who had emperors wasn’t a group of countries.

Can you tell me what is or are the essential (functional and institutional) difference(s) between Emperor and King so that I can give a belated answer to my grand-daughter?

Answer 1

Bringing together a couple of good answers, the primary differences between a King and an Emperor are:

• A king rules one "country" or "nation"; an emperor rules over many. This is implicit in the definition of "kingdom" vs "empire"; an empire is always made up of multiple countries that have come under full control of one governing body (typically under one man, sometimes under a small group such as a triumvirate). So, to be an emperor, you have to have an empire; typically you go from "king" to "emperor" by conquering your nearest neighbors.

• A king normally rules by birthright; an emperor normally rules by conquest. Note the use of the word "normally". Kingdoms change hands between ruling families; the British Royal Family count ancestors from several formerly-competing houses, meaning that along the way several people crowned king or queen were so crowned after defeating relatives or even entirely different families (in fact perhaps the most famous line of British monarchs, the Tudors, are extinct in the male line; Edward VI, Mary I and Elizabeth I all died childless, and James VI of Scotland, Elizabeth's first cousin twice removed, ascended the throne under the House of Stuart). However, in the normal course of events, the line of succession of rule is by blood; principles of primogeniture apply more often to lines of kings than emperors. Emperors, by the nature of an empire, usually become so by conquest; you start out ruling one country, and then you invade another and replace their former system of government with one controlled by you. The line of succession of emperors can be either by blood (dynastic) or by continued conquest; the Roman Empire is a mix of succession by blood and by usurpment. The key difference is that dynastic rule is usually less important in an empire than simply whomever has the most power and influence within it as of the death or deposition of the sitting Caesar. If the previous Caesar was well-liked, then whomever he has groomed for power (whether a child or a close friend) is likely to ascend. If the previous Caesar was disliked, or didn't leave a clear line of succession, then the situation is ripe for a power grab by a previously less influential faction which then promotes its own leader into the position.

EDIT FROM COMMENT: Actually, the title of Emperor does fit with Japanese history. Prior to the 11th century, Japan was a collection of feudal states basically ruled by the landowners. The Emperor was appointed by these aristocrats to resolve disputes and provide a "unified voice" over these many feudal lands. In the early 11th century, the Kamakura shogunate was formed in the aftermath of the Genpei War, which took governmental power from the aristocrats and Emperor and placed it with the military akin to a junta. During this time, and the following Ashikaga and Tokugawa shogunates, the feudal states on the islands of Japan became unified into what we now know as a single country, and the Emperor's position evolved into more of a spiritual leader akin to the Pope. The importance of bloodline was always central (which does indicate a king), but as the Emperor became the head of the Shinto faith the bloodline came to signify the Emperor's status as a descendant of Amaterasu, and thus having divine legacy but not necessarily the mandate to govern.

In the late 1860s the Tokugawa shogunate fell and power to govern was restored to the Emperor (at the time Emperor Meiji, hence the "Meiji Restoration"). From this time until the end of WWII, Japan did indeed become a true empire, extending beyond the home islands to assert control over Manchuria, most of Southeast Asia and the Indonesian archipelago. The treaty that ended WWII allowed the Japanese people to retain their Emperor as a cultural icon, but stripped the office of all power to govern. The position and its trappings are defined in the current constitution as "a symbol of the Japanese state" akin to the British Crown, but while the Crown retains some key sovereign powers like command of the armed forces, the power to veto and to dissolve Parliament, etc, the Japanese Emperor performs mainly ceremonial and diplomatic duties and has no sovereign power whatsoever.

Answer 2

King and Emperor are both European titles, with their own (tangled) European history.

King is a Germanic word, derived from the Proto-Indo-European root *genə-, 'birth'. It's related to the English words kin, kind, gentle, etc, as shown in this diagram.

Emperor is a Latin word, derived from the verb imperāre, meaning 'to rule'. The original Latin word was Imperātor, meaning 'ruler'. The term Emperor has been used by many people, in many countries, to describe a ruler who is more powerful than an ordinary King, at least in the opinion of the Emperor, and possibly in the minds of the people he rules.

Essentially, the difference between King and Emperor is like the difference between wonderful and terrific — both are good, and one may be better than the other; but opinion differs about which is which.

Answer 3

The difference you mentioned is correct. It's important to note, however, that an emperor doesn't necessarily have to be an emperor of countries, in the modern sense. I believe, in the examples of Japan and China, the empires arose when the territory we now refer to as countries was actually a large collection of independent city-states and other small sovereign bodies. The empires arose to impose some degree of universal authority over all those sovereignties, but left some amount of autonomy and private governance in place.

Both imperial and monarchial families can and have been considered royalty or more (for example, many empires have regarded their emperors as deities.

Answer 4

To the linguistic changes, mentioned by John Lawler, I have to add small detail: both King and Emperor (Kingdom and Empire) have full sense only inside Europe. For other regions they are only more or less correct translation.

You know better than others, that "Emperor of Japan" is european-style title of Tennō, which can be dirty translated into English as "heavenly sovereign". Same details applied also to China-Iran-...

And I want to fix OALED (what is it?) definition. Emperor can rule both: a group of formally independent countries (Napoleon) and a multinational unitary state, created from independent in past countries (or pre-state entities). Formally empires have more territory, more population, a more diverse national structure without overwhelming numerical dominance of individual nation

Answer 5

I was under the impression, but I can't figure out where from now that:

• A Duke rules an area by having a force that the Duke total controls but is normally a vasel of a Prince
• A Prince was the holder of several Duchies or a Princedom (where the Dukedoms are fiefs) and is the lowest level of a Sovereign, ie rules a area with complete control
• A King was holder of several Princedoms or a Kingdom
• An Emperor was holder of several Kingdoms or an Empire. An Emperor is regard as a Higher King.

but this might be a reverse engineered definition.

Answer 6

It might be helpful to take a corpus-based approach. As a corpus, I have a book from 1904 which reproduces the congratulations sent by heads of state in 1902 to the first President of Cuba. The styles of the various European monarchs challenge some of the suggestions made in other answers in this thread. The letters are written in various languages, but as has been mentioned in other answers there's some common ground between European nations on the terms.

Wilhelm, von Gottes Gnaden DeutscherKaiser [Emperor], König [King] von Preuken, etc: etc: etc:

Franciscus Josephus Primus Austriae Imperator [Emperor], Bohemiae Rex [King] de et Apostolius Rex [Apostolic King] Hungariae

Ferdinand 1ª Prince de Bulgarie

Au nom du Roi [King], Christian Prince de Danemark Régent

Don Alfonso XIII, por la gracia de Dios y la Constitución Rey [King] de España

Edward, by the Grace of God, of the United Kingdom of Great Britain and Ireland and of the British Dominions beyond the Seas King, Defender of the Faith, Emperor of India, &c., &c., &c.

George 1^er Roi [King] des Hellenes

Vittorio Emanuele III, per grazia de Dio e per volontà della Nazione Re [King] d'Italia

Nicolas I^er Prince de Monténégro

Wilhelmina, bÿ de gratie Gods, Koninginder [Queen] Nederlanden, Prinses [Princess] van Oranje-Nassau, enz., enz. enz.

Dom Carlos por Graça de Deus, Rei [King] de Portugal e dos Algarves, d'Aquem e d'Alem Mar em Africa Senhor [Lord] de Guiné e da Conquista Navegação e Commercio da Ethiopia Arabia, Persia e da India, etc.

Alexandre I. Roi [King] de Serbie

Oscar, med Guds Nade Sveriges, Norges, Gotes och Vendes Konung [King]

I've skipped one, for brevity and to save transcribing the Cyrillic: Nikolai II of Russia's style can be summarised as: Emperor and Autocrat of all the Russias, of Moscow, Kiev, and a couple of other cities, Tsar of 6 cities/regions/countries, Lord of Pleskov, Grand Duke of five cities/regions/countries, Duke of 11 named places and "others", and we're only half-way through (see note 3).

The first thing which strikes me, and which is consistent with the observation that empires are the result of expansion which engulfs other kingdoms, is that all of the "Emperors" (Wilhelm, Franz Joseph, Edward, Nikolai) also call themselves kings of specific territories. For example, Hungary was part of what we would call the Austro-Hungarian Empire, but its relationship with its ruler was defined in terms of the (historically significant and unique title) Apostolic Majesty rather than the Empire.

The second thing to note is that the four empires were all hereditary, which stands in stark contradiction to some of the assertions made in other answers.

The third point of interest are the principalities. In the case of Bulgaria, which might seem surprising (it's a fairly large place, after all), this is explained by being a vassal of the Ottoman Empire, and it became a Kingdom when it declared its independence in 1908. Denmark is the one which really sparks my curiosity: why did the king style himself a prince?

One common factor of the empires is that they were large and that they included an almagamation of previously independent states. But the same is true of at least two of the kingdoms: Spain (I've seen plenty of references on monuments to Rex Hispaniorum - King of the Spains; and if he wanted to push it then Alfonso could have had a list to rival Nikolai's); and Italy (only recently unified). Both of those kings use a single title in their style, and they're the only monarchs to attribute their rule to something more than the grace of God. The inference can be made that they're intentionally emphasising the unity of their domains and their link with the common people.

In short, an attempt to reduce the distinction between a king and an emperor to a simple criterion seems likely to fail. It seems to be largely a question of historical continuity, politics, and etiquette.

Answer 7

I wouldn't try to attach precise definitions to such "job titles". The president of France has very different powers than the president of the United States. An American consul is a very different job from the ancient Roman consul. For that matter, the powers of the Queen of England today have little relation to the powers of the Queen of England when Victoria or Elizabeth I held the office.

This is doubly so when the title is a translation from another language.

Answer 8

Historically, the main difference between "king" and "emperor" might have been how they came into office.

A king usually becomes king because his family has been the ruling family, and he ascends to the throne because he is next in line after the old king (who died). Usurpers are an exception but would call themselves king because they would found a new dynasty. (Similarly for queen, of course.)

An emperor in old Rome, where the term arguably originated, that is an "imperator" was a successful general. He would carry the title from victory until his glorious return to Rome.

Dictator was an office that the Roman senate would staff with a suitable candidate in times of (military) need; this was similar to modern martial law. The mandate would end after a predetermined period of time (if not extended).

Caesar is a title (which is the origin of German "Kaiser") which was used in its modern meaning only after Gaius Iulius Caesar (where "Caesar" is only a name), who was dictator first, (illegally) became sole ruler of the Roman Empire, beginning the era of Caesars.
In the Holy Roman Empire the "Kaiser" was elected by the principal dukes ("Kurfürsten") and arch bishops (and then appointed by the (a, at times) pope).

In modern English, the terms "emperor" and "caesar/Kaiser" have somehow merged. The meaning of "dictator" shifted considerably (arguably due to office abuse in the past). The main difference (historically) between those and kings seems to be that the former are granted (or earned) titles while kingship is inherited.

Of course, tyrants declare themselves anything they want so there have certainly been other appellations.

Answer 9

Emperor is the King of kings. China and Japan was not a country but countries before an emperor united them under an empire. However, a king can upgrade himself as emperor anyway.

Answer 10

I would add to the other excellent answers that, at lease to my mind, King implies, as noted by @JohnLawler, birth. Ruling by bloodline. Whereas an Emperor generally seems to have risen to station via political or military might. Even though they may have started life as a King, they can upgrade to Emperor by taking over other countries, as in the case of England and India.

Answer 11

You may be interested in the concept of Divine Right, which (to me, as a citizen of a monarchy) implies that the King is there to be complementary to and wholly part of the nation, and vice versa. It suggests that the natural state of being for a country is to have a King, as specified by God. This presumption does not necessarily apply to Emperors, whom are acknowledged to come to power by the machinery of politics, including birthright, or conquest.

In other words, whether or not this idea is accepted academically, it seems to me that the idea of a King is more closely tied to the concept of nationhood than that of an Emperor.

(I am not entirely happy with my terminology, as I think the concept of 'nationhood' is probably newer than that of Kings, and encompasses a more complete idea of politics and representation compared to the realm that Kings are supposed to preside over in the concept of Divine Right. In this respect, since rulers of self-defined Nations have called themselves Emperor, I need an older word for the domain of a King.)

Answer 12

Both kings and emperors can be self-proclaimed, for example Godred Crovan medieval ruler of Dublin and the Isles and Bokassa I of the short lived 20th century Central African Empire (previously and subsequently the Central African Republic) among many others.

The difference between a king or emperor who goes on to found a dynasty and one who is overthrown or deposed is, firstly, his ability to persuade or threaten his own people to support him and, secondly, his ability to persuade established rulers and / or governments to recognise and support him. Crovan ruled successfully and founded a dynasty which lasted nearly two centuries; Bokassa set up an empire which lasted less than three years.

There is no clear, independent definition of the difference between a king and an emperor, just what the people who set up and continued the kingdom or the empire could get away with.