was made by Hadrian a title, conferred on the heir presumptive to the throne (A.D. 136). Diocletian conferred the title on the two viceroys, calling the two emperors Augustus (sacred majesty). The German Emperor still assumes the title of kaiser (q.v.).
“Thou art an emperor, Cæsar, keisar, and Pheezar.” —Shakespeare: Merry Wives of Windsor, i.3.
“No bending knees shall call thee Caesar now.”
Shakespeare: 3 Henry VI., iii. 1.
Caesar, as a title, was pretty nearly equivalent to our Prince of Wales and the French dauphin.
Caesar's wife must be above suspicion. The name of Pompeia having been mixed up with an accusation against P. Clodius, Cæsar divorced her; not because he believed her guilty, but because the wife of Cæsar must not even be suspected of crime. (Suetonius: Julius Cæsar, 74.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Caesar from Infoplease: