Caesar is a title used for a Roman emperor from about 30 B.C. to 70 A.D., derived from the line of Julian. There were several Caesars: Tiberius, Caligula, Claudius I, and Nero. The word then became the title to designate the Ruler of the Roman Empire. References to Caesar in the Bible can be found in Matt. 22:17; Luke 2:1; John 19:12; Acts 25:11-12; etc.