Caesar, a title that came from the name of a Roman family. The first important member of the family was the soldier and statesman Gaius Julius Caesar. His nephew and adopted son, Octavian, took the name Caesar and was awarded the title Augustus by the Senate when he became Rome's first emperor. The next four emperors—Tiberius, Caligula, Claudius, and Nero—also were descendants of Julius Caesar's sister. The family came to an end when Nero died in 68 A.D. After that, Caesar became a title only. It was given, after 136, to the person next in line to the throne. The word Caesar eventually became czar (tsar) in Russia and kaiser in Germany.