According to legend, the city of Rome was founded in 753 BC by Romulus and Remus on the Palatine Hill along the Tiber River. Rome transitioned through a monarchy, republic, and empire over the centuries. As a republic from 509 to 27 BC, Rome was ruled by elected officials and grew to control the Mediterranean world through military conquests. Augustus became Rome's first emperor in 27 BC, beginning the Roman Empire that lasted until 476 AD, spreading Roman culture across Europe, North Africa and the Middle East while experiencing political and economic crises before its fall.