An inquiry into the etymology of this name is of some interest, as no other name has ever obtained such celebrity — ""clarum et duraturum cum aeternitate mundi nomen."" It was assumed by Augustus as the adopted son of the dictator, and was by Augustus handed down to his adopted son Tiberius. It continued to be used by Caligula, Claudius, and Nero, as members either by adoption or female descent of Caesar's family; but though the family became extinct with Nero, succeeding emperors still retained it as part of their titles, and it was the practice to prefix it to their own name, as for instance, "Imperator Caesar Domitianus Augustus". When Hadrian adopted Aelius Verus, he allowed the latter to take the title of "Caesar"; and from this time, though the title of "Augustus" continued to be confined to the reigning prince, that of "Caesar" was also granted to the second person in the state and the heir presumptive to the throne.