Emperor of the Roman Empire
Former Monarchy Imperial
Augustus First monarch Last monarch Augustus Theodosius I (Unified or Classical), Romulus Augustulus (Western), Constantine XI (Eastern) Imperator, Augustus, Caesar, Princeps, Dominus Noster, or Autokrator (depending on period)
Monarchy started 27 BC Monarchy ended AD 395 (Unified or Classical), AD 476 (Western), AD 1453 (Eastern)
Current pretender None
The Roman emperor was the ruler of the Roman State during the imperial period (starting at about 27 BC). The Romans had no single term for the office although at any given time, a given title was associated with the emperor. If a man was "proclaimed emperor" this normally meant he was proclaimed augustus, or (for generals) imperator (from which English emperor ultimately derives). Several other titles and offices were regularly accumulated by emperors, such as caesar, princeps senatus, consul and Pontifex Maximus. The power of emperors was generally based on the accumulation of powers from republican offices and the support of the army. Roman emperors refused to be considered "kings", instead claiming to be leaders of a republic, however nominal. The first emperor, Augustus, resolutely refused recognition as a monarch. Although Augustus could claim that his power was authentically Republican, his successor, Tiberius, could not convincingly make the same claim. Nonetheless, the Republican institutional framework (senate, consuls, magistracies etc.) was preserved until the very end of the Western Empire. By the time of Diocletian, emperors were openly "monarchs", but the contrast with "kings" was maintained: Although the imperial succession was, de facto, generally hereditary, it was only hereditary if there was a suitable
Roman emperor candidate acceptable to the army and the bureaucracy so the principle of automatic inheritance was not adopted. The Eastern (Byzantine) emperors ultimately adopted the formal title of Basileus, which had meant king in Greek, but became a title reserved solely for the "Roman" emperor (and the ruler of the Sassanid Empire). Other kings were referred to as regas. In addition to their pontifical office, emperors were given divine status: initially after their death, but later from their accession. As Christianity prevailed over paganism, the emperor's religious status changed to that of Christ's regent on earth, and the Empire's status was seen as part of God's plan to Christianize the world. The Western Roman Empire was dealt fatal blows by a set of military coups d'état in the Italian Peninsula in 475 and 476. The division of the empire into Western and Eastern was formally abolished as a separate entity by Emperor Zeno after the death of the last Western Emperor Julius Nepos in 480. Zeno's successors ruled from Constantinople (modern Istanbul) through the conquest of that city by the Ottoman Turks in 1453. The last Roman Emperor, Constantine XI died in hand to hand combat defending the capital. A dynasty of claimants maintained the Imperial tradition in the province of Chaldia through its conquest by the Ottomans in 1461.
Rome used no single constitutional office, title or rank exactly equivalent to the English title "Roman emperor". Romans of the Imperial era used several titles to denote their emperors, and all were associated with the pre-Imperial, Republican era. "Roman emperor" is a convenient shorthand used by historians to express the complex nature of the person otherwise known as princeps - itself a republican honorific. The emperor's legal authority derived from an extraordinary concentration of individual powers and offices extant in the Republic rather than from a new political office; emperors were regularly elected to the offices of consul and censor. Among their permanent privileges were the traditional Republican title of princeps senatus (leader of the Senate) and...