Title: Caesar (title)
Content:  For political and personal reasons, Octavian chose to emphasize his relationship with Julius Caesar by styling himself simply "Imperator Caesar" (whereto the Roman Senate added the honorific Augustus, "Majestic" or "Venerable", in 27 BC), without any of the other elements of his full name. His successor as emperor, his stepson Tiberius, also bore the name as a matter of course; born Tiberius Claudius Nero, he was adopted by Caesar Augustus on 26 June 4 AD, as "Tiberius Julius Caesar". The precedent was set: the Emperor designated his successor by adopting him and giving him the name "Caesar". The fourth Emperor, Claudius, was the first to assume the name "Caesar" upon accession, without having been adopted by the previous emperor; however, he was at least a member by blood of the 
Title: Regnal name
Content:  The Roman Emperors usually had the titles of "Imperator Caesar Augustus" in their names (which made their regnal names). Caesar came from the cognomen of Gaius Julius Caesar, Imperator meant Commander and Augustus meant venerable or majestic. The name usually went in two ways, Imperator (Praenomen, Nomen and Cognomen) Caesar Augustus or Imperator Caesar (Praenomen, Nomen and Cognomen) Augustus. Also, Imperator became a Praenomen of Roman Emperors, Augustus and Caesar became a cognomen of theirs.
Title: Gaius Julius Caesar (name)
Content:  historians, he himself never used either of his original surnames again), and the name of Caesar became fused with the imperial dignity after Octavianus became the first Roman Emperor, Augustus; in this sense it is preserved in the German and Bulgarian words Kaiser and Tsar (sometimes spelled Czar), both of which refer to an emperor. Compare the Hungarian, Slavic and Turkish words for "king", forms of kral, all adapted from Karl, the personal name of Charlemagne. The name of the dictator Julius Caesar—Latin script: CAIVS IVLIVS CAESAR—was often extended by the official filiation Gai filius ("son of Gaius"), rendered as Gaius Iulius Gai 
Title: Emperor
Content: Caesar (as, for example, in Suetonius' Twelve Caesars). This tradition continued in many languages: in German it became "Kaiser"; in certain Slavic languages it became "Tsar"; in Hungarian it became "Császár", and several more variants. The name derived from Julius Caesar's cognomen "Caesar": this cognomen was adopted by all Roman emperors, exclusively by the ruling monarch after the Julio-Claudian dynasty had died out. In this tradition Julius Caesar is sometimes described as the first Caesar/emperor (following Suetonius). This is one of the most enduring titles: Caesar and its transliterations appeared in every year from the time of Caesar Augustus to Tsar Simeon II of 
Title: List of Roman emperors
Content:  century. The modern word 'emperor' derives from the title imperator, which was granted by an army to a successful general; during the initial phase of the empire, the title was generally used only by the princeps. For example, Augustus' official name was Imperator Caesar Divi Filius Augustus. The territory under command of the emperor had developed under the period of the Roman Republic as it invaded and occupied much of Europe and portions of North Africa and the Middle East. Under the republic, the Senate and People of Rome authorized provincial governors, who answered only to them, to rule regions of the empire. The chief magistrates of the republic were two 
Title: Caesar (title)
Content:  dynasty, being the maternal great-nephew of Augustus on his mother's side, the nephew of Tiberius, and the uncle of Caligula. Claudius in turn adopted his stepson and grand-nephew Lucius Domitius Ahenobarbus, giving him the name "Caesar" in the traditional way; his stepson would rule as the Emperor Nero. The first emperor to assume the position and the name simultaneously without any real claim to either was the usurper Servius Sulpicius Galba, who took the imperial throne under the name "Servius Galba Imperator Caesar" following the death of the last of the Julio-Claudians, Nero, in 68 AD. Galba helped solidify "Caesar" as the title of the designated heir by giving it to his own adopted heir, Lucius Calpurnius Piso Frugi Licinianus. Galba's reign did not last long and he was soon 
Title: Imperator
Content:  title Emperor of India, British monarchs would follow their signatures with the initials RI, standing for rex imperator ("king-emperor"). George VI of the United Kingdom was the last European ruler to claim an imperial title; when he abdicated as Emperor of India in 1948, the last active use of the title imperator in the West ceased. It was thereafter used only historically, or as a Latin translation for certain continuing titles of non-European cultures, such as Japan. The imperial title was also adopted by Jean-Bédel Bokassa, during his reign as the emperor of the short-lived Central African Empire (1976–79).
Title: Roman emperor
Content:  granted by the Senate, passed to Caesar's adopted heir along with his name and virtually synonymous with it. In 38 BC, Agrippa refused a triumph for his victories under Octavian's command, and this precedent established the rule that the princeps should assume both the salutation and title of imperator. It seems that from then on Octavian (later the first emperor Augustus) used imperator as a first name (praenomen): Imperator Caesar not Caesar imperator. From this the title came to denote the supreme power and was commonly used in that sense. Otho was the first to imitate Augustus, but only with Vespasian did imperator (emperor) become the official title by which the ruler of the Roman Empire was known.
Title: Emperor Seiwa
Content:  Before his ascension to the Chrysanthemum Throne, his personal name (his imina) was Korehito (惟仁), the first member of the Imperial house to be personally named "-hito" 仁. One meaning of the character 仁 is the Confucian concept of ren. Later it has been a tradition to name the personal name of all male members of the Imperial family this way. He was also known as emperor as Mizunoo-no-mikado or Minoo-tei.
Title: Emperor
Content:  emphatically crowned himself Tsar of Russia on 16 January 1547. The word "Tsar" derives from Latin Caesar, but this title was used in Russia as equivalent to "King"; the error occurred when medieval Russian clerics referred to the biblical Jewish kings with the same title that was used to designate Roman and Byzantine rulers — "Caesar". On 31 October 1721, Peter I was proclaimed Emperor by the Governing Senate. The title used was Latin "Imperator", which is a westernizing form equivalent to the traditional Slavic title "Tsar". He based his claim partially upon a letter discovered in 1717 written in 1514 from Maximilian I to Vasili III, in which the 

Question: what was the emperor name in star wars?
Answer: Darth Sidious.
Sheev Palpatine.