The Roman Republic transitioned into the Roman Empire with the establishment of the principate system in 27 BCE, when Octavian was granted the title of Augustus by the Roman Senate, marking the beginning of the imperial era.
How long did the Roman Empire last?
The Roman Empire endured for approximately five centuries, until the Western Roman Empire's collapse in 476 CE due to various internal and external factors. However, the Eastern Roman Empire, also known as the Byzantine Empire, continued to exist until 1453 CE when Constantinople fell to the Ottoman Turks.