when did the roman empire split into two parts
Western Roman Empire In historiography, the Western Roman Empire refers to the western provinces of the Roman Empire at any time during which they were administered by a separate independent Imperial court, coequal with that administering the eastern provinces, referred to as the Eastern Roman Empire. The terms "Western Roman Empire" and "Eastern Roman Empire" are modern inventions that describe political entities that were de facto independent. At no point did the Romans themselves consider the Empire to have been split into two separate Empires. They considered it remained a single state that was governed by two separate Imperial courts as an administrative expediency. A system of government of this kind is known as a diarchy.
Roman Republic The Roman Republic (Latin: Res publica Romana; Classical Latin: [ˈreːs ˈpuːb.lɪ.ka roːˈmaː.na]) was the era of classical Roman civilization beginning with the overthrow of the Roman Kingdom, traditionally dated to 509 BC, and ending in 27 BC with the establishment of the Roman Empire. It was during this period that Rome's control expanded from the city's immediate surroundings to hegemony over the entire Mediterranean world.