When did the Roman Empire start and finish?

The Roman Empire started in 27 B.C. and ended in A.D. 393. This period began with Gaius Julius Caesar Octavianus being awarded the title of Augustus.

The Roman Empire is divided into two major periods. During the earlier half, known as the Principate, the governing system in place still bore similarities to that of a republic. In the latter half of the Imperial period, called the Dominate, the empire had already changed and was closer to a monarchy. Other well-known emperors of this period after Augustus were Claudius, Claudius II, Julian, Maximinus and Leo. The last Roman emperor of the West was Romulus Augustulus.