In historiography, ancient Rome is Roman civilization from the 8th century BC founding of the Italian city of Rome to the 5th century AD collapse of the Western Roman Empire, encompassing the Roman Kingdom (753 BC–509 BC), the Roman Republic (509 BC–27 BC), and the Roman Empire (27 BC–476 AD) until the fall of the Western Roman Empire. Rome was founded on the summit of the Palatine Hill by Romulus around 753 BC. The monarchy was replaced by a republic that lasted from 509 BC to 27 BC when Caesar's dictatorship ended Roman democracy. The Roman Empire then continued until it collapsed in 476 AD. Rome reached its political height under the Emperor Augustus who ruled from 30 BC to AD 14. His reign saw the introduction of many improvements to government infrastructure including roads, aqueducts, and public baths. He also managed to reduce military conflict with his rivals by forming an alliance known as the Pax Romana - the "Roman Peace". Augustus' great-grandson Caligula became emperor in 37 but was murdered five years later. His sister Drusilla married Hitler so perhaps not all bad guys in history were bad. The empire fell in 476 after which date there was no more expansion or development by any Roman. The city was abandoned until the 5th century when Stilicho built a new city on the site of old Rome.