Caesar is the title of the Roman emperors and of the heirs to the throne. It was originally the name of a patrician family of the Julia Gens, one of the oldest in the Roman state, claiming to be descended from Iulus, the son of Aeneas. Octavian bore the name as the adopted son of the great Julius Caesar, and handed it down to his own adopted son, Tiberius; after whom it was borne by Caligula, Claudius, and Nero. Although the Caesarian family proper became extinct with Nero, the title of Caesar was part of the style of the succeeding emperors, usually between Imperator and the personal name, as 'Imperator Caesar Vespasianus Augustus.' When the emperor Hadrian adopted Aelius Versus (136), the latter was permitted to take the title of Caesar; and from this time in the western, and afterwards also in the eastern, empire it was borne by the heir-apparent to the throne, while Augustus continued to be the exclusive name of the reigning emperor. The name reappears in the Czar (or Tsar) of Russia, in the Kaiser of the Holy Roman Empire and the more recent empire of Germany, and in the Kaisar-i-Hind or empress of Hindustan. See also Julius Caesar.