The Holy Roman Emperor, originally and officially the Emperor of the Romans during the Middle Ages, and also known as the Roman-German Emperor since the early modern period, was the ruler and head of state of the Holy Roman Empire. The title was held in conjunction with the title of king of Italy from the 8th to the 16th century, and, almost without interruption, with the title of king of Germany throughout the 12th to 18th centuries.
Longest reigning Frederick III 19 March 1452 – 19 August 1493
Coats of arms of prince electors surround the imperial coat of arms; from a 1545 armorial. Electors voted in an Imperial Diet for a new Holy Roman Emperor.
Depiction of Charlemagne in a 12th-century stained glass window, Strasbourg Cathedral, now at Musée de l'Œuvre Notre-Dame.
Illustration of the election of Henry VII (27 November 1308) showing (left to right) the Archbishop of Cologne, Archbishop of Mainz, Archbishop of Trier, Count Palatine of the Rhine, Duke of Saxony, Margrave of Brandenburg and King of Bohemia (Codex Balduini Trevirorum, c. 1340).
The title of imperator originally meant the rough equivalent of commander under the Roman Republic. Later, it became a part of the titulature of the Roman Emperors as their praenomen. The Roman emperors themselves generally based their authority on multiple titles and positions, rather than preferring any single title. Nevertheless, imperator was used relatively consistently as an element of a Roman ruler's title throughout the Principate and the Dominate. The word itself derives from the stem of the verb imperare, meaning 'to order, to command'. The English word emperor derives from imperator via Old French: Empereür.
Carving in Diana Veteranorum referring to Lucius Verus as Imperator
