Mark Antony in the context of "Tomb of Antony and Cleopatra"

During the classical period, the Roman Empire controlled the Mediterranean and much of Europe, Western Asia, and North Africa. The Romans conquered most of these territories in the time of the Republic, and it was ruled by emperors following Octavian's assumption of power in 27 BC. Over the 4th century AD, the empire split into western and eastern halves. The western empire collapsed in 476 AD, while the eastern empire endured until the fall of Constantinople in 1453.

By 100 BC, the city of Rome had expanded its rule from the Italian peninsula to most of the Mediterranean and beyond. However, it was severely destabilised by civil wars and political conflicts, which culminated in the victory of Octavian over Mark Antony and Cleopatra at the Battle of Actium in 31 BC, and the subsequent conquest of the Ptolemaic Kingdom in Egypt. In 27 BC, the Roman Senate granted Octavian overarching military power (imperium) and the new title of Augustus, marking his accession as the first Roman emperor. The vast Roman territories were organized into senatorial provinces, governed by proconsuls who were appointed by lot annually, and imperial provinces, which belonged to the emperor but were governed by legates.

The denarius (Latin: [deːˈnaːriʊs]; pl.: dēnāriī, Latin: [deːˈnaːriiː]) was the standard Roman silver coin from its introduction in the Second Punic War c. 211 BC to the reign of Gordian III (AD 238–244), when it was gradually replaced by the antoninianus. It continued to be minted in very small quantities, likely for ceremonial purposes, until and through the Tetrarchy (293–313).

The word dēnārius is derived from the Latin dēnī "containing ten", as its value was originally of 10 assēs. The word for "money" descends from it in Italian (denaro), Slovene (denar), Portuguese (dinheiro), and Spanish (dinero). Its name also survives in the dinar currency.

The Battle of Actium was a naval battle fought between Octavian's maritime fleet, led by Marcus Agrippa, and the combined fleets of both Mark Antony and Cleopatra. The battle took place on 2 September 31 BC in the Ionian Sea, near the former Roman colony of Actium, Greece, and was the climax of over a decade of rivalry between Octavian and Mark Antony.

In early 31 BC, the year of the battle, Antony and Cleopatra were temporarily stationed in Greece. Mark Antony possessed 500 ships and 70,000 infantry and made his camp at Actium, while Octavian, with 400 ships and 80,000 infantry, arrived from the north and occupied Patrae and Corinth, where, with the help of Marcus Vipsanius Agrippa, he managed to cut Antony's southward communications with Egypt via the Peloponnese. Octavian had previously gained a preliminary victory in Greece, where his navy successfully ferried troops across the Adriatic Sea under the command of Agrippa. Octavian landed on mainland Greece, opposite the island of Corcyra (modern Corfu), and proceeded south on land.

The War of Actium (32–30 BC) was the last civil war of the Roman Republic, fought between Mark Antony (assisted by Cleopatra and by extension Ptolemaic Egypt) and Octavian. In 32 BC, Octavian convinced the Roman Senate to declare war on the Egyptian queen Cleopatra. Her lover and ally Mark Antony, who was Octavian's rival, gave his support for her cause. Forty percent of the Roman Senate, together with both consuls, left Rome to join the war on Antony's side. After a decisive victory for Octavian at the Battle of Actium, Cleopatra and Antony withdrew to Alexandria, where Octavian besieged the city until both Antony and Cleopatra were forced to commit suicide.

The war involved some of the largest Roman armies ever seen. Both Antony and Octavian's legions were experienced veterans of previous civil wars who had fought together, many also having once served under Julius Caesar. The two did however raise their own legions separately.

Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (Latin: Octavianus), was the founder of the Roman Empire, who reigned as the first Roman emperor from 27 BC until his death in AD 14. The reign of Augustus initiated an imperial cult and an era of imperial peace (the Pax Romana or Pax Augusta) in which the Roman world was largely free of armed conflict. The Principate system of government was established during his reign and lasted until the Crisis of the Third Century.

Octavian was born into an equestrian branch of the plebeian gens Octavia. Following the assassination of Julius Caesar in 44 BC, Octavian was named in Caesar's will as his adopted son and heir, and inherited Caesar's name, estate, and the loyalty of his legions. He, Mark Antony, and Marcus Lepidus formed the Second Triumvirate to defeat the assassins of Caesar. Following their victory at the Battle of Philippi (42 BC), the Triumvirate divided the Roman Republic among themselves and ruled as de facto oligarchs. The Triumvirate was eventually torn apart by the competing ambitions of its members; Lepidus was exiled in 36 BC, and Antony was defeated by Octavian's naval commander Marcus Agrippa at the Battle of Actium in 31 BC. Antony and his wife Cleopatra, the Ptolemaic queen of Egypt, killed themselves during Octavian's invasion of Egypt, which then became a Roman province.

The constitutional reforms of Augustus were a series of laws that were enacted by the Roman Emperor Augustus between 30 BC and 2 BC, which transformed the Constitution of the Roman Republic into the Constitution of the Roman Empire. The era during which these changes were made began when Augustus defeated Mark Antony and Cleopatra at the Battle of Actium in 31 BC, and ended when the Roman Senate granted Augustus the title "Pater Patriae" in 2 BC.

The history of the Roman Empire covers the history of ancient Rome from the traditional end of the Roman Republic in 27 BC until the abdication of Romulus Augustulus in AD 476 in the West, and the Fall of Constantinople in the East in 1453. Ancient Rome became a territorial empire while still a republic but was then ruled by emperors, beginning with Octavian Augustus, the final victor of the republican civil wars.

Rome had begun expanding shortly after the founding of the Republic in the 6th century BC, though it did not expand outside the Italian Peninsula until the 3rd century BC, during the Punic Wars, after which the Republic expanded across the Mediterranean. Civil war engulfed Rome in the mid-1st century BC, first between Julius Caesar and Pompey, and finally between Octavian (Caesar's grand-nephew) and Mark Antony. Antony was defeated at the Battle of Actium in 31 BC, leading to the annexation of Egypt. In 27 BC, the Senate gave Octavian the titles of Augustus ("venerated") and Princeps ("foremost"), thus beginning the Principate, the first epoch of Roman imperial history. Augustus' name was inherited by his successors, as well as his title of Imperator ("commander"), from which the term "emperor" is derived. Early emperors avoided any association with the ancient kings of Rome, instead presenting themselves as leaders of the Republic.

The history of Rome includes the history of the city of Rome as well as the civilisation of ancient Rome. Roman history has been influential on the modern world, especially in the history of the Catholic Church, and Roman law has influenced many modern legal systems. 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 magistrates. The period was marked by vast expansion of Roman territory. During the 5th century BC, Rome gained regional dominance in Latium. With the Punic Wars from 264 to 146 BC, ancient Rome gained dominance over the Western Mediterranean, displacing Carthage as the dominant regional power.
• The Roman Empire followed the Republic, which waned with the rise of Julius Caesar, and by all measures concluded after a period of civil war and the victory of Caesar's adopted son, Octavian, in 27 BC over Mark Antony.
• The Western Roman Empire collapsed in 476 after the city was conquered by the Ostrogothic Kingdom. Consequently, Rome's power declined, and it eventually became part of the Eastern Roman Empire, as the Duchy of Rome, from the 6th to 8th centuries. At this time, the city was reduced to a fraction of its former size, being sacked several times in the 5th to 6th centuries, even temporarily depopulated entirely.
• Medieval Rome is characterised by a break with Constantinople 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 the High Middle Ages, 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 occurred in the 15th century, when Rome replaced Florence as the centre 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 part of the First French Empire from 1809 to 1814.
• Modern history, the period from the 19th century to the present. Rome came under siege again after 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 (as of 2015; 2.9 million within city limits), it is the largest city in Italy. It is among the largest urban areas of the European Union and classified as a global city.