Caesar was one of the titles of Roman emperors, placing them in continuity with Julius Caesar.
From Caesar derive after ancient times the names of certain emperors or rulers:
* Kaiser in Germany,
* Tsar (spelled Czar before 1914) in Russia, Bulgaria and Serbia,
* Csiszár, pronounced tchissar in Hungary,
* Kaysar in the Ottoman Empire
Caesar's title in the Roman Empire
This name commonly designates Julius Caesar and the eleven emperors who reigned from -27 to +98:Augustus, Tiberius, Caligula, Claudius, Nero, Galba, Otho, Vitellius, Vespasian, Titus and Domitian, although the last six of these princes are entirely foreign to Caesar's family. Suetonius wrote the Lives of the Twelve Caesars.
From Augustus, Caesar is one of the praenomina (which comes before the family nomen - it is not the exact equivalent of the first name) of the emperors, generally in the company of imperator.
In 293, the Emperor Diocletian introduced the Tetrarchy:two Caesars were appointed as deputy emperors of the two Augusti. This organization did not survive the ruin of the Tetrarchy from 306, when Constantine was proclaimed Caesar by the troops of his father, Constantius Chlorus.
Constantine I reused the title, but to give imperial status to his sons and install them in certain regions of the empire in order to represent him there.
His son, Constance II, made Caesars his cousins Gallus, then Julian. Their status was intermediate between that of the Caesars of the Tetrarchy and that of the heir princes of Constantine:members of the imperial family, thereby endowed with the more or less magical aura specific to emperors, they were its representative, had a certain power, but were also subject to very strict control. After the execution of Gallus for his errors in Antioch and the usurpation of Julian, the following emperors no longer had recourse to this device, which they no doubt considered dangerous. Thus, when Theodosius I wanted to elevate his son Arcadius to a first step to the throne, he did so directly Augustus.
The title of Caesar in the Byzantine Empire
In Constantinople, Heraclius (610-641) gave up bearing the titles of Caesar and Augustus (title) and the Latin title, in favor of the title of basileus. The title of Caesar nevertheless remains in the Byzantine titulary, and comes immediately after that of basileus.
During an exceptional ceremony in Constantinople, it was conferred for the first time on a barbarian prince, the Bulgarian khan Tervel by Justinian II (705-711) as a reward for the help the khan had given him to recover the imperial throne. .
Subsequently, the title of Caesar was granted only on very rare occasions, and only to an important member of the imperial family. From the 11th century, with the proliferation of honorary titles, the title of Caesar moved back in the hierarchy:Alexis I Comnenus by creating the title of sebastokrator moved him to 3rd place. Then Manuel I Comnenus demoted him to 4th place by granting the title of despot. Finally Andronicus II Paleologus again devalues the title Caesar by granting it to Roger Flore, leader of the Catalan mercenaries.