[Verginius Rufus]

The last of the traditional Roman dictators (maximum term six months) were in the period of the Second Punic War in the late third century. After that you have Sulla and Julius Caesar holding dictatorships without a time limit. After Caesar's assassination, the office was abolished.

When Octavian, Marc Antony, and Lepidus joined forces in late 43 B.C., they created the Triumvirate which was in effect a three-man dictatorship, but they avoided the term "dictator." Eventually Octavian had sole control but in fashioning a legal basis for his authority after 31 B.C., he avoided the term "dictator." He had learned from his uncle's mistakes.

[danielmryan]

Thanks; I'm not as much up on Roman history as I should be. It makes sense that the office would fall into desuetude, because Rome the city was no longer threatened with invasion.

You're right about him not using the exact same title; he went with Imperator, which used to be reserved for generals whose victories rated a triumph. Still, the custom - although in disuse - was there to be tapped into. Augustus could claim, plausibly, to have brought an end to the civil wars that had rent the late Republic.