An emperor (Latin: Imperator; "commander") is either:
- The head-of-state of Rome in the last centuries of its power,
- One who rules over a nation-state above a certain size, especially one containing multiple subordinate "kingdoms," or
- One who heads a government commanding a vast land area taken by conquest.
Originally the Latin title of Imperator was a title of spontaneous acclaim that the soldiers of a Roman army bestowed upon their commander immediately after they had won a great victory. If, in addition to this, the army had achieved a requisite number of enemy casualties and collected a requisite amount of booty, such a commander was entitled to the grandest celebration that the Roman people granted to their leading generals: the triumph.
Then in 38 BC, a young Roman politician named Gaius Julius Caesar Octavianus began calling himself Imperator Cæsar Divi Filius - "Commander, Son of the Divine Caesar." This was in reference to the murder and deification of his grand-uncle, the celebrated Julius Caesar, in 44 BC. Eventually this man became the head of state and the first to carry the title of Augustus. Beginning with him, the headship-of-state became hereditary in all but name.
More to the point, among the distinctions that the new Roman monarchs reserved for themselves was the exclusive right to celebrate triumphs, with all that triumphs entailed—the lengthy parades, the sacrifice to the king of the gods, et cetera. Because one entitled to celebrate a triumph had to have been called Imperator, that became one of the titles (though not, strictly speaking, the official one) that the head-of-state claimed. From this we derived the English word "Emperor" and various versions of that word in other languages.
Official and Unofficial Titles
The official title that a Roman Emperor claimed was Princeps Senatus, literally, Prime Head of the Senate. Originally that title had belonged to the senior sitting Senator and was largely ceremonial. But now the Roman Emperors claimed to be the leaders of the Senate, and also to invest that title with dictatorial power.
In addition, every Roman emperor since Augustus always carried the cognomens "Caesar" and "Augustus," in honor of Emperor Augustus and his great-uncle, Julius Caesar. Some say that the elder Caesar was the first Emperor, but this is not correct. The man known to history as Julius Caesar was made Dictator of Rome for life, but that title did not have all of the powers that Augustus and his successors held.
Perquisites of Office
An Emperor was a senior magistrate, and especially one having imperium—the distinction of being immune from any reversal of his discharge of the powers and duties of his office. The Emperor was also the highest such magistrate. To symbolize his exalted rank, he walked about with an escort of twenty-four yeomen, called lictors, each carrying a specially bound bundle of thirty rods, one for each of the original thirty tribes of Rome. In each bundle lay an axe, the symbol of the authority of the magistrate being so escorted to pronounce sentence of death.
More than this, a Roman Emperor was also the Chief Censor. In this capacity he was not so much a moral arbiter as he was the man in charge of the Roll of Citizens, and the officer ultimately in charge of tax and other rolls. Most tellingly of all, he could make and unmake Senators.
Finally, a Roman Emperor usually discharged the office now known as tribune of the people (originally "tribune of the plebs"). In that capacity he had the authority to approve or to forbid any piece of legislation. The Latin verb translating "I forbid" is veto—hence the use of that word in English to denote the act by an executive of "forbidding" a legislative act to become law.
During the Middle Ages, the great King Charlemagne established the Holy Roman Empire, an attempt to re-create the Roman state as a union of French and German peoples. Accordingly, he called himself "Emperor." The Holy Roman Empire was actually a federation of subordinate kingdoms, and the later empires of Germany and Austria-Hungary followed this pattern.
In the nineteenth century, Napoleon Bonaparte took the title of Emperor to signify his intention of conquering the known world. Finally, the Tsars of Russia demanded that people address each of them as "His Imperial Majesty," a form of address clearly indicating that the office of Tsar was equivalent to that of an emperor.
- Emperor by Merriam-Webster Online Dictionary