Roman history has been among the most influential to the modern world, from supporting the tradition of the rule by law to influencing the American Founding Fathers to the creation of the Catholic church. Roman history can be divided into the following periods:
- Pre-historical and early Rome, covering Rome's earliest inhabitants and the legend of its founding by Romulus.
- The period of Etruscan dominance and the Regal Period, in which according to tradition, Romulus was the first of seven kings.
- The Roman Republic, which commenced in 509 BC when kings were replaced with rule by elected senators. The period was marked by vast expansion of Roman territory. During the 5th century BC, Rome gained regional dominance in Latium, and eventually the entire Italian peninsula by the 3rd century BC. With the Punic Wars from 264 to 146 BC, Rome gained dominance over the Western Mediterranean, displacing Carthage as the dominant regional power.
- The Roman Empire: With the rise of Julius Caesar, the Republic waned and by all measures, concluded after a period of civil war and the victory of Octavian, the adopted son of Caesar in 27 BC over Mark Antony. After the collapse of the Western Roman Empire, Rome managed to hang onto the empire, still known as the Roman Empire but long centered on the eastern Mediterranean, until the 8th century as the Duchy of Rome. At this time, the city was reduced to a fraction of its former size, being sacked several times in the 5th to 6th centuries, in 546 even temporarily depopulated entirely.
- Medieval Rome: Characterized by a break with Byzantium and the formation of the Papal States. The Papacy struggled to retain influence in the emerging Holy Roman Empire, and during the Saeculum obscurum, the population of Rome fell to as low as 30,000 inhabitants. Following the East–West Schism and the limited success in the Investiture Controversy, the Papacy did gain considerable influence in high medieval Europe, but with the Avignon Papacy and the Western Schism, the city of Rome was reduced to irrelevance, its population falling below 20,000. Rome's decline into complete irrelevance during the medieval period, with the associated lack of construction activity, assured the survival of very significant ancient Roman material remains in the centre of the city, some abandoned and others continuing in use.
- The Roman Renaissance: In the 15th century, Rome replaced Florence as the symbol of artistic and cultural influence. The Roman Renaissance was cut short abruptly with the devastation of the city in 1527, but the Papacy reasserted itself in the Counter-Reformation, and the city continued to flourish during the early modern period. Rome was annexed by Napoleon and was technically part of France during 1798–1814.
- Modern History: The period from the 19th century to today. Rome was under siege by the Allied invasion of Italy and was bombed several times. It was declared an open city on 14 August 1943. Rome became the capital of the Italian Republic (established in 1946), with a population of 4.4 million in its metropolitan area (as of 2015; 2.9 million within city limits)—is the largest city in Italy. It is among the largest urban areas of the European Union and classified as a "global city".